In late May, an Iraqi cleric called Akram Kaabi visited militia fighters in a desolate Iraqi town near the Syrian border. Kaabi, who heads a Shi'ite Muslim militia named Harakat Hezbollah al Nujaba, was decked out in a camouflage uniform and led the fighters in prayer on mats laid on the dusty ground. A video of the session showed heavily armed militiamen standing guard.The event took place in Qayrawan, a town the Nujaba militia had seized back from Islamic State, the radical Sunni Muslim group. Nujaba, whose name means 'the Virtuous,' have also fought across the border in Syria, where they have lent support to President Bashar al-Assad in the fight against Islamic State and others.The Nujaba group, which has about 10,000 fighters, is now one of the most important militias in Iraq. Though made up of Iraqis, it is loyal to Iran and is helping Tehran create a supply route through Iraq to Damascus, according to Iraqi lawmaker Shakhwan Abdullah, retired Lebanese general Elias Farhat, and other current and former officials in Iraq. The route will run through a string of small cities including Qayrawan. To open it up, Iranian-backed militias are pushing into southeast Syria near the border with Iraq, where US forces are based. The Nujaba militia is one example of the way Iran is seeking to expand its Shi'ite influence in Iraq and across the wider region. In the 1980s, Shi'ite-dominated Iran was at war with Iraq, where Sunni Muslims held power despite being a minority of the population. But after the fall of Saddam Hussein, the Shi'ite majority in Iraq took control of the government.Since then, ties between the Shi'ite-led governments in Tehran and Baghdad have become stronger, and Iran has acquired growing influence in Iraq. Iranian money and religious backing are now key to the Iraqi government's power.Kaabi has repeatedly said that Nujaba is allied with Iran. Last autumn, he said his group follows "Velayat-e Faqih," or Guardianship of the Jurist, the ideological cornerstone of Iran's theocratic system of government, according to the Iranian Tasnim news agency.Current and former Iraqi officials told Reuters they worry Nujaba will help Iran make a decisive strategic breakthrough. "If Iran can open this road they will have access through Iraq and Syria all the way to Hezbollah in Lebanon," said Farhat, the retired Lebanese army general.Iran, which backs Syria's Assad, has stated that it wants to see its influence extend through Iraq to its allies in Damascus and beyond to Hezbollah, a Shi'ite militant group in Lebanon it has long supported.A security adviser who works with a number of governments in the Middle East said Iran needs road access to Damascus to supply the conflict in Syria. "There is a very high cost for air transport for the militias. Troops and small supplies are easy to transport but it's hard to load heavy weapons on airplanes," said the adviser, who asked not to be identified because of the sensitivity of the subject."The goal is to open a road on both sides for logistics ... They want to bring in artillery, rockets and heavy equipment like bulldozers," the adviser said.In Iraq, the Nujaba fights under the umbrella of the Popular Mobilization Forces (PMF), which encompass tens of thousands of Shi'ite militiamen. Last year Iraq's parliament passed a law that put these fighters under the control of the Iraqi government. But current and former officials in Iraq and militia members say many of the militias have been armed and trained by Iran's Revolutionary Guards.A representative at an Iranian Revolutionary Guards office in Tehran declined to comment on the Nujaba militia.Iraqi Prime Minister Haider al-Abadi and other senior Iraqi officials have not spoken out in public about Nujaba or the new road. But some players within Iraq's governing coalition want to distance Iraq from Iran.Ayad Allawi, a vice president, is Shi'ite, but he has a nationalist outlook and wants to prevent the conflict in Syria from spilling over further into Iraq. He said in an interview: "The government of Iraq should prevent them (Shi'ite militias) from going to Syria. We are not supposed to supply fighting people to support a dictatorship in Syria." Asked to comment on Iran-backed militias moving into southeast Syria near where American forces are based, US Army Colonel Ryan Dillon, a spokesman for the US-led coalition fighting Islamic State, said: "The Coalition reserves the right to protect itself and its vetted Syrian partners against any threat."A US State Department official said: "The United States remains deeply concerned about the Iranian regime's malign activities across the Middle East which undermine regional stability, security and prosperity."The current route that Iran is pushing to open through Iraq was not its first choice. Soon after Iran became involved in the Syria conflict in 2011, the Iranians attempted to open a logistical supply line through the Kurdish region of northern Iraq to Syria, lawmaker Abdullah, who is a member of the Iraqi parliament's security and defense committee, told Reuters. But Massoud Barzani, the president of the Kurdistan region of Iraq, resisted the move, said Abdullah, who is a member of Barzani's Kurdistan Democratic Party (KDP).The new route bypasses the Kurdish region but could still destabilize the country, according to Abdullah."All the groups in Iraq other than Shi'ites will be under threat if Iran can make this road," Abdullah said. "Sunnis will be displaced. The Kurdistan region will be under threat and Christians will be under threat."