DURING ONE week in April – the second one – it seemed that Israel and Iran were set to be engaged in a direct confrontation. In the early hours of Monday, April 10, it was reported that the Israel Air Force struck a military base known as T-4 near the city of Homs in Syria. Fourteen people were killed, seven of them Iranian “advisers” – including a colonel in charge of drone operations in Iran’s Islamic Revolutionary Guard Corps (IRGC). The attack came just hours after the world was shocked to hear and see how the brutal regime of Syrian President Bashar Assad once again used chemical weapons on its citizens. First, it was speculated that it was a punitive action by the IAF on behalf of the US against the regime for its use of the forbidden weapons.Israel, in line with its opaque policy of neither denying nor confirming its involvement in Syria, didn’t claim responsibility. Nevertheless, it was widely accepted that the IAF carried out the attack. A week later, an Israeli security official was quoted by The New York Times as confirming that indeed it was an Israeli attack aimed at damaging the Iranian installation. The T-4 base is known to Israeli intelligence to be a “hub” for Iranian military deployment in Syria. Most probably, the base is related to drones and air defense. Senior Iranian officials, including Ali Akbar Valiati – a former foreign minister and special adviser on international matters to Supreme Leader Ali Khamenei – vowed to retaliate. Russia, which together with Iran is the main sponsor of the Syrian regime, also reacted angrily. While in the past it seemed that Russia was tolerating Israeli air strikes against shipments of weapons to Hezbollah and turning a blind eye, this time the Russian army provided precise operational details about the air strike and accused Israel of undermining security and stability in Syria and the region. Surprised by the seemingly harsh Kremlin reaction, Israeli Prime Minister Benjamin Netanyahu picked up the phone and called Russian President Vladimir Putin. It was their 50th phone conversation in the last three years, in addition to seven face-to-face meetings. The last phone call was the first indication that the tension in the quadrangular Iran-Syria-Russia- Israel relations was being defused. Both leaders promised not to escalate the situation any further. Then came the US-led Western missile attack against Syrian chemical weapon installations, and Putin had a bigger headache to deal with.For years, as reported, Iran and Israel had been engaged in a clandestine “cold war,” which involved assassinations, sabotage and terror acts carried out by secret agents or their proxies in the Middle East, Asia, Africa, Europe and South America. They fought over Iran’s nuclear program, Hezbollah in Lebanon and the Palestinian issue. But during the last two years, the two enemies found themselves battling in a new arena – Syria. As the seven-year civil war in Syria has been limited in its scope while Assad’s regime regained more territory and stabilized its control, both Israel and Iran began to prepare for “the day after.” Iran, which together with Russia has been Assad’s savior, has consolidated its direct and indirect military presence in Syria, hoping to be granted not only economic concessions but also air, naval and land military bases, including ones close to the border with Israel. Israel, on the other hand, has declared that it cannot tolerate direct front lines with Iran, in addition to its front with the pro-Iranian Hezbollah in Lebanon. Until two years ago, according to foreign reports, most Israeli involvement – its “red lines” – in Syria was to retaliate against Assad’s forces for any errant or intentional fire launched against its territory on the Golan Heights as well as striking from the air shipments of missiles sent from Iran via Syria to Hezbollah. But recently, as Iran tried to deepen its military posture in Syria, in general, and close to the Israeli border, in particular, Israel set a new red line. Israeli leaders and military chiefs declared that they were concerned about Iranian efforts to consolidate their military presence in Syria.In the beginning, Israel hoped that the US would act on its behalf and protect its interests by persuading the Russians to push the Iranian presence and bases away from the Israeli border. But the new administration of Donald Trump either wasn’t attentive enough to Israeli sensitivities or didn’t care. Either way, Israel realized that it is on its own and has to take care of its own interests. Thus, reportedly as early as 2017, the IAF began to target bases, air fields and military equipment of the Iranian forces in Syria. Israel was especially concerned about the deployment in Syria of Iranian drones and anti-aircraft systems, which may limit the freedom of action and maneuverability of its air force. In late 2017, it was reported that Israeli planes struck an empty base, which was alleged to be hosting Shi’ite warriors from Pakistan, Iraq and Afghanistan under Iranian command, and a factory that was producing precision missiles and their components. Then, in February 2018, for the first time, both nations went out into the open over skies to exchange military punches. Iran launched a drone from its “hub” in the T-4 airfield, near Homs, which also accommodates Syrian and Russian forces, into Israel. Israeli air defenses followed the drone, known as a small version of Iran’s larger Shaed 129, which it boasted had stealth capabilities, immediately after its take-off, and when it entered Israeli territory, shot it down. On the eve of the US-led attack on Syria, the Israeli military announced that the Iranian drone had been equipped with explosives and its target had been a military site. In response, Israeli war planes fired missiles and destroyed the drone’s command center at T-4. On their way back, one of the US-made F-16s was shot down by Syrian air defenses. While Israel revealed almost all details of the incident, Iran denied it completely, claiming it hadn't happened at all and was just “Israeli propaganda.”The situation is still very fragile. Israeli officials assume that Iran, with its “elephant memory,” will seek revenge for the killing of its servicemen at a time and place that suits its interests and not necessarily in Syria. It can try to attack Israeli diplomats and embassies, as it did in 1992 by bombing the Israel Embassy in Buenos Aires. But at the moment, Tehran doesn’t wish to stir up more trouble and complicate matters while it anxiously waits for the US president’s decision in May whether to walk away from the nuclear deal. Nevertheless, both Israel and Iran are determined to pursue their conflicting interests. Iran’s interests are to continue to deploy its forces in Syria in order to safeguard its Shi’ite land corridor all the way from its territory via Iraq and Syria to Lebanon and the Mediterranean coast. Israel, on the other hand, is resolute not to allow Iran to deepen its presence in Syria. In that sense, there is no difference between the Israeli cabinet led by Netanyahu and Defense Minister Avigdor Liberman and the military chiefs. Both share the same perception and goal.Russia, which is stuck in the middle, is trying to mediate between the two sides. Putin knows very well that if Israel’s security concerns are not resolved, Israel holds the key with its capability to destabilize Syria. In a way, Israel is holding Assad hostage vis-à-vis Russian interests to support him. But Putin also knows and understands Iranian interests in Syria and his mission – to accommodate both – is as complicated as squaring the circle.