The Euphrates River is a simmering front line in the struggle for the new Syria.

It separates the country’s two largest armed camps, marking the physical divide between clashing visions for the future. On one side is the army of the new Damascus government, dominated by Islamist factions who took down a dictatorship. On the other are the forces of a region run by Kurds, ready to guard their hard-won independence with their lives.

With tensions rising, Reuters journalists traveled 1,800 kilometers across this divide in the summer, visited key strategic centers on both sides of the waterway, and interviewed dozens of military and civilian officials, activists, and displaced people.

They found a lawless frontier under the control of armed groups with scores to settle, local tensions that confound leaders’ hopes for unity, and soldiers prepared to kill each other before they give ground.

At their closest point, these forces stand 200 meters apart, stationed at either end of a dirt bridge across the Euphrates in the divided eastern city of Deir Ezzor. When the reporting team approached, fighters on both sides had received orders to close it to all traffic, but none of the men would explain why. They agreed to allow a crossing only after repeatedly examining press credentials.

The city of Deir Ezzor, which straddles the Euphrates River, in eastern Syria June 14, 2025.
The city of Deir Ezzor, which straddles the Euphrates River, in eastern Syria June 14, 2025. (credit: Khalil Ashawi/Reuters)

Fighters on the government side of the dirt bridge stood with weapons drawn and cocked, including one aggressive gunman with bloodshot eyes who was trying to stop a crowd of locals pushing to leave the Kurdish side. Cross-river gunfire has wounded several fighters and civilians in the weeks since. Each side accuses the other of starting it.

Ahmed al-Hayis, a commander in the new Syrian army who oversees Deir Ezzor, is stationed on the western bank of the Euphrates. Kurdish forces control his ancestral land on the other side of the river. He keeps a submachine gun by his side, a pistol and knife holstered to his belt, and surrounds himself with hardened Islamist fighters.

“In Damascus, they talk about liberation,” he said, referring to the fall of Syrian dictator Bashar al-Assad. “Here, we’re still occupied.”

To the river’s east, Sozdar Derik, a commander of the Kurdish women’s battalions, was taking her own precautions – she didn’t have a mobile phone so she couldn’t be tracked and changed location regularly. She said she’ll never trust Hayis and his comrades, whom she has battled in the past.

“We won’t attack, but we’ll defend ourselves,” Derik said. “We’re ready for war.”

The two camps facing off across the river emerged as the most powerful after the toppling of Assad in December.

Islamist former rebel factions control nearly all the areas to the west of the Euphrates – roughly two-thirds of Syria, including its major cities and the Mediterranean coast. They dominate the new government in Damascus led by President Ahmed al-Sharaa, a former Al Qaeda commander. They seek full control of the country and have the backing of the US administration and NATO member Turkey.

Kurdish-led militants hold roughly one-third of the country mostly to the east of the Euphrates, including hydroelectric dams that help power Syria and oil wealth crucial to its future. They run their own regional administration and want to keep it that way. They are US-trained but fear abandonment by American allies.

In meeting rooms, negotiators from both sides are struggling to advance a faltering unity agreement signed in March. The deal, now being negotiated in Damascus, would merge Kurdish-led forces into the Islamist-dominated military of Sharaa’s government.

On the ground, signs point to a long-term partition or to confrontation. Neither outcome would bring the stability or unity so many Syrians desperately hoped would follow Assad’s fall.

Clashes took place at each point the reporting team visited along the Euphrates frontline, both in the weeks before and after the journalists were there. While the cross-river skirmishes broke out in Deir Ezzor, Kurdish forces upstream killed a relative of an Arab commander Reuters interviewed in a fresh gun battle. The commander sent men and weapons to the front in response. Turkey meanwhile staged its first airstrikes in months on Kurdish positions, and the Kurds dug new defensive tunnels.

The months since Assad’s toppling in December have already tempered hopes for a peaceful transition. The new government’s security forces crushed a pro-Assad insurgency by killing hundreds of members of the Alawite minority in coastal areas. Bloodshed involving Druze gunmen, Bedouin tribes, and Israeli airstrikes recently destabilized the south.

The Euphrates skirmishes threaten to ignite a bigger battle. On either side are tens of thousands of fighters funded, trained and armed at different stages in the Syrian civil war by the US and its allies.

Syria’s government did not respond to requests for comment about the Euphrates divide. In an interview earlier this month with Syrian state television, Sharaa said negotiations had stalled and that international partners were getting involved, including the United States and Turkey.

“Anything that will help avoid a battle or war in this problem, I’ve done it,” he said. “In the end, Syria will not give up a single inch of its land.”

Farhad Shami, spokesman for the Kurdish-led Syrian Democratic Forces, questioned whether a unified Syrian military was possible.

“The disagreement with them is not purely military but a difference of identity in the true sense,” he said in a statement to Reuters.

Syrians fear that fresh foreign meddling, local warlords and factional violence could yet tip the country into renewed conflict.

“My family told me things had gotten better,” said Tariq, an engineering graduate who returned from Turkey this year to Deir Ezzor, his ruined hometown that is now split by the river between Islamist and Kurdish control.

“I don’t feel safe,” he said. “I wish I’d not come back.”

Syrian Democratic Forces commander Khalil Qahraman surveys the Tishreen Dam on the Euphrates River in northern Syria, June 7, 2025.
Syrian Democratic Forces commander Khalil Qahraman surveys the Tishreen Dam on the Euphrates River in northern Syria, June 7, 2025. (credit: REUTERS/Orhan Qereman)

THE NORTHERN FRONT: FACEOFF AT A DAM

The reporting team began its journey upstream, where Assad’s ouster reignited a dormant war within a war that now stands at a shaky stalemate around a leaky dam on the Euphrates.

The river once fed ancient civilizations. Now, it provides water and power to modern-day Turkey, Syria and Iraq, making its control a key lever of regional power.

As rebels led by future president Sharaa stormed Damascus in December, Turkey-backed groups under a separate command fought Kurdish forces in a land grab in northern Syria. They drove the Kurds from territory they’d held west of the river, including near the city of Aleppo, around 100 kilometers back to the Tishreen Dam.

Since December, Kurdish authorities told Reuters, 418 of their fighters and 57 civilians, plus three journalists, have died in clashes, most of them in the first weeks of chaos.

The reporters visited the former Kurdish-held enclaves before heading east towards the Euphrates, following the line of the Kurdish retreat. The first stop was at the base of a Turkey-backed Arab commander who spearheaded the advance.

“They didn’t put up much resistance,” the commander, Motasem Abbas, said of the Kurdish forces.

Abbas spoke a few weeks before the Syrian defense ministry barred military officials from meeting with the media without prior approval.

Abbas commands around 2,000 fighters in areas that stretch from his hometown of Marea near Aleppo to the Euphrates. He was promoted in the spring to brigade commander in the Syrian army’s new 80th Division, a role that puts him formally in control of this northern section of the frontline with the Kurds.

Big and athletic, Abbas is 38 and has fought since he was 24. He names the Assad regime and the Islamic State, the extremist group that seized and controlled territory in Syria from 2014 to 2019, as his two most hated enemies. But with them gone, his adversary is the Kurdish-led Syrian Democratic Forces.

“If the SDF ceases to exist, then Syria can begin to revive,” Abbas said.

Despite a tentative truce around the dam, he said, Kurdish forces kept sending drones to spy on or attack his troops. Kurdish authorities said they initiated no attacks and were responding to actions from Syrian government forces.

He also now has a personal grudge: His second cousin was killed in clashes with the Kurds last month, he said. “He was shot through the back,” Abbas said. “We’re sending more men and weapons to reinforce.”

Kurdish authorities denied any involvement in the fighting and blamed the death on an internal dispute among the government factions over influence. Reuters could not confirm the circumstances of the death.

Abbas’s compound is a collection of low-rise buildings with armored personnel carriers and gun-mounted pickups parked outside. It is netted by wiring to protect against drone attacks. He travels in armored cars flanked by bodyguards. He now officially reports to the defense ministry in Damascus, but maintains a strong allegiance to his main foreign backer, Turkey, who people on both sides say long provided his group with arms and ammunition.

Multiple security officials across both sides of the Euphrates divide said Turkey also pays monthly wages to fighters of about 3,000 Turkish pounds ($80). The Turkish government didn’t respond to requests for comment, about the salaries or other details of its efforts in Syria.

In Abbas’s office, a plaque perched on a cabinet described President Tayyip Erdogan in broken Turkish as the “Muslim Caliph,” for his “heroic stance towards the Syrian people.”

The Turkey-backed brigades and their feud with the Kurds are by-products of the Syrian civil war. When the peaceful anti-Assad uprising of 2011 descended into conflict, Western countries, Gulf Arab states and Turkey armed a dizzying array of rebel factions.

That rebel kaleidoscope eventually coalesced into two main Islamist alliances: Hayat Tahrir al-Sham, the group led by new President Sharaa; and the Syrian National Army, a collection of factions armed and trained by Turkey, and now a junior partner in the new government.

Ethnic tension inside Turkey has bled into northern Syria for years, with a long-stated Turkish goal to drive Kurdish militants from the border. Syrian Kurdish militants have ties to the PKK, a separatist militant group that Turkey has fought at home for decades and is now engaging in talks.

Abbas said the Kurdish issue loomed largest among the problems facing Syria.

The road between Abbas’ forces and the Kurds features vast stretches of countryside with few military checkpoints. Near the town where Abbas’s second cousin died, a group of rag-tag militants with no insignia extracted money from motorists for safe passage.

At the Tishreen Dam, Kurdish forces stationed there blamed recent fighting on the Turkey-backed factions and said they had been shelled six times by their rivals.

“The last attack against us was a week ago, artillery fire,” said Khalil Qahraman , the commander on site. In the weeks since, there have been further exchanges of fire in the area, including Turkish airstrikes around the dam for the first time in months.

The dam supplies nearby towns under Kurdish control with electricity, engineers on site said, but if fixed – and if the sides came to an agreement – it could nourish war-ravaged Syrian cities to the west and east. For that, it needs a regular flow from Turkey upstream, and foreign parts to fix leaks around its turbines, which have reduced power generation, the engineers said.

Qahraman , a seasoned fighter with graying hair and a weathered face, was still stinging from being forced to retreat by Abbas and other Turkey-backed factions . He was also rattled by US plans to pull American troops from northeast Syria who have been backing the Kurds for over a decade in the fight against Islamic State. Reporters saw two newly emptied US bases during the journey.

Qahraman said his forces are prepared to fight on their own against all enemies to protect the dam.

“We built up experience fighting Islamic State, and now we’re gaining more fighting these factions. We’ve been developing new tactics,” he said.

They also have new weapons, namely a fleet of drones Qahraman and two other commanders said were launched for the first time in December and proved crucial to halting the Turkey-backed groups’ advance at the dam. Qahraman said the US-led coalition helped develop them.

The US military did not respond to a request for comment about arming the Kurdish forces or other questions about its activities in the region.

Kurdish forces are also resorting to more traditional defenses. The sound of picks and shovels echoes in the hills around the Tishreen Dam, where workers are carving new tunnel networks.

The subterranean pathways are just wide enough for a broad-shouldered fighter and his gear. The tunnels burrow at least 30 meters underground. The tunnel diggers have designs for a network that would branch between hills every 100 meters or so.

Armed members of the Syrian Democratic Forces' (SDF) military police take part in a demonstration under the banner “With our will, we will protect our revolution.” in Qamishli, Syria, September 17, 2025.
Armed members of the Syrian Democratic Forces' (SDF) military police take part in a demonstration under the banner “With our will, we will protect our revolution.” in Qamishli, Syria, September 17, 2025. (credit: REUTERS/Orhan Qereman)

EASTERN FRONT: SCORES TO SETTLE

About 300 kilometers downstream in Deir Ezzor, the Turkey-backed Syrian army commander Hayis, better known by his nom de guerre Abu Hatem Shaqra, looks across the Euphrates at his home village and nurses a grudge.

“President al-Sharaa always had his eye on Damascus. Mine is on my land occupied by the SDF. I’ll fight a hundred times harder for this,” said Hayis, sitting surrounded by bearded fighters in an officer’s mess that once served Assad’s army.

Deir Ezzor lies towards the southeastern end of the Euphrates divide, at the farthest reaches of Damascus’s control. Nearly 500 kilometers of sparsely populated desert long exploited by Islamic State separate the capital from this neglected city, whose ruined streets are half-empty after years of war, with reconstruction yet to begin.

To reach it, the reporters drove through the desert, which included a makeshift checkpoint that local residents said had only been operating a few days. The residents didn’t recognize the militants manning it.

Since Assad fell, Deir Ezzor has been split along the river’s natural boundary into zones controlled by Hayis’s men and by Kurdish-led forces.

The dirt bridge Reuters reporters crossed during its chaotic closure, and the militants on the other side, are all that separates Hayis from the ancestral prize he seeks.

The Damascus government in May appointed Hayis to lead the 86th Division in the new Syrian military, putting him in control of a 150 kilometer stretch of territory along the Euphrates, from just outside Raqqa, Islamic State’s former Syrian capital, to Deir Ezzor.

Raqqa and Deir Ezzor’s eastern countryside are areas that Hayis, the Damascus government and Turkey believe should never have come under Kurdish control.

Kurdish militants and Assad’s forces fought at the start of the civil war, then mostly avoided each other, allowing the Kurds to carve out a form of self-rule. The US later made the Kurdish forces its main proxy against Islamic State.

As Islamic State retreated after 2017, Kurdish-dominated forces grabbed territory the jihadist group had held around the Euphrates, prompting Turkish invasions, in which Hayis participated.

Hayis’s appointment angered the Kurds because he integrated former Islamic State members into his ranks and because they accuse him of committing human rights abuses, including against Kurds.

Hayis acknowledged recruiting former Islamic State militants, but said it was revenge for the group co-opting many of his fighters during the civil war. He resents Kurdish forces for getting the lion’s share of US support to fight Islamic State when he and his comrades were also battling the group.

He denied committing human rights abuses and said he didn’t worry that Western outrage over abuse allegations might cost him his appointment. “How can al-Sharaa take it away from me? We gave him his power by agreeing on him as president,” said Hayis, who also spoke to Reuters before the defense ministry order about speaking to journalists.

Hayis has been plotting ways to undermine the nearby Kurdish-led forces: he hopes to encourage defections from their Arab contingent – a tactic he says met with success in the past. “I’m watching and listening. I have my people placed in their territory.”

Kurdish forces on the opposite bank at this stretch of the front are taking no chances.

On the outskirts of Raqqa, more tunnels were being dug and trucks were carting prefab concrete shelters towards the city. The local administration headquarters is nestled in a compound surrounded by blast walls, with panoramic views of the river – and any advancing forces deployed by Damascus.

Further away, at the Kurdish military headquarters, Derik, the commander of the women’s contingent, said the appointment of Hayis and his Turkey-backed comrades to senior military positions was a provocation by the new government.

“There are sanctions on these people. They should be tried in international courts,” she said.

Derik worried that Hayis’s appointment was a signal that the new Syrian government intended to seize Deir Ezzor, Raqqa, and Hasaka from Kurdish forces. “No military commander should be imposed on a region,” she said.

Derik has painful memories of fighting Hayis’s men, who seized territory from the Kurds as part of a Turkish invasion in 2019, the last time US President Donald Trump ordered a major withdrawal of troops from Syria.

She said she could never join a Syrian military staffed by Hayis and a large contingent of other Turkey-backed commanders.

Derik pinned new hopes for holding off Hayis and his forces on drones and tunnels. Despite the Kurdish retreat, she said the drones used in December were a good test against the Turkish-backed forces and managed to bypass their radar jamming.

“They were a nightmare for the enemy,” she grinned.

CONFLICTING VISIONS

Away from the front lines, Kurdish politician Foza Yusuf and Damascus government official Masoud Battal are facing off across the negotiating table.

Their task: to bring these commanders together under one military and merge the Kurdish-led administration into the Damascus government.

They are under intense pressure from the United States, which has advocated a unified Syria.

“The United States is interested in a peaceful, prosperous, and stable path forward for Syria. This won’t happen without Syrian unity,” a State Department official said in a statement to Reuters.

In a briefing this week with Reuters and other reporters, Sharaa said there is no alternative for Syria.

"There cannot be room for opportunities to divide us right now, not by factional minorities," he said.

But Yusuf and Battal, and their teams, have clashing visions for their country.

Battal runs a district near Aleppo flanked by Turkish military bases, where a large Turkish flag billows right next to the local town hall. A colleague of his said that Turkey as late as June was still paying the salaries of many local officials.

His part of Syria is policed by militants with long, Salafi-style beards who see the Kurdish-run region as a separatist project that refuses to relinquish Syria’s oilfields and uses the threat of an Islamic State resurgence as a bargaining chip to keep US support. Kurdish forces hold almost all the Islamic State fighters and families captured in Syria when the extremist group folded. Trump wants the new Syrian government to assume that responsibility.

Battal harbors personal hatred for Kurdish forces.

“They imprisoned me in 2013 and tried to force me to become a fighter,” said Battal, himself a Kurd from the northeastern city of Qamishli. He fled for northwestern Syria and joined the Islamist rebel factions instead. Reuters couldn’t independently confirm his account. The SDF denied Battal was ever arrested.

The district he runs, majority-Kurdish Afrin, has been a flashpoint for ethnic tensions since Turkey-backed forces ejected Kurdish troops in 2018.

Battal, like many new officials in territory under the control of Damascus, holds some conservative Islamist beliefs.

“There’s a level of freedom for women that even the West wouldn’t want” in Kurdish-controlled areas, he said, referring to equal divorce rights for men and women. He also criticized Kurdish recruitment of young women fighters.

Yusuf, a Kurdish woman, resides in the Kurdish part of Syria and fervently believes in equal rights for women and minorities.

She and her colleagues see the Damascus government as Islamists close to a hostile Turkey and not serious about combating Islamic State. “In Damascus, the revolution is over. Here, it’s not finished. We need to secure these rights,” Yusuf said.

But her region is also heavily policed, bureaucratic and beset with its own ethnic tensions. At checkpoints near Raqqa, Kurdish security forces questioned Arabs. At one, masked gunmen arrested an elderly man and drove him away in the back of a pickup truck.

In the battered urban centers on each side of the divide, Syrians don’t know if they’re safer with the Islamists or the Kurds.

Some Alawites from western Syria fled to Kurdish-controlled areas after the killings in March. Kurdish politicians also offered support to Druze civilians during clashes with tribal and government forces in July.

But others are beginning to resent the rule of the Kurdish-run government.

“Authorities here arrest innocent people in the name of security, and use the threat of Islamic State as an excuse,” said Mariam, a Raqqa resident who helps run a local rights group.

She showed Reuters written permissions from the Kurdish-led administration for her group to hold their meetings, which stipulated that they provide a monthly report on their activities, and said authorities often demanded to know what was being discussed. She gave only her first name for fear of reprisals. The SDF said local authorities request to know the time and date of meetings to ensure public safety.

Mariam has lived under the rule of Assad, Islamic State, and now the Kurds. Two of her brothers went missing after being arrested by Islamic State. Another was killed by a US airstrike while queueing for water in Raqqa, she said.

She doesn’t like any of the options facing her.

“Syria’s headed towards partition. If you visit cities under the control of the new government in Damascus, you’re suspected by the Kurds. If you live in this region, you’re a Kurdish-affiliated enemy to the other side,” she said.

Mariam’s city straddles the Euphrates at its midpoint, surrounded by fertile land and controlling roads across the northeast. Whenever there’s war in Syria, it is a prize.

“We’re stuck in the middle,” she said.