The Syrian air base near Homs that sustained an airstrike Monday night is where Iran is trying to set up a large air force compound under its exclusive control.

Syria, Iran and Russia all blamed Israel for the strike, which killed at least four advisers from the Iranian Revolutionary Guards’ Quds force. Arab media reports said one was a colonel with a senior position in the Revolutionary Guards’ drone operation in Syria. The Lebanese television station Al-Manar, which is affiliated with Hezbollah, reported seven Iranians killed, and the real number could be even greater.

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In addition to the Revolutionary Guards, the large base, known as T4, hosts contingents of the Syrian and Russian air forces. The Iranians, who operate independently, are relatively far away from the Russians; they control the base’s western and northern sides. That’s apparently why Russia’s statements specified that the airstrike hit the western side of the base.

Open gallery view Twitter picture of the targeted Iranian base in Syria, according to Iranian media. Credit: Fars News Agency

On February 10, after an Iranian drone was downed inside Israeli territory, the Israeli air force bombed the drone’s command post, located at T4. According to foreign media reports, that strike also killed some Iranians, though that time Iran itself didn’t announce the deaths.

Both strikes, coupled with a series of international media reports quoting “Western intelligence officials,” reveal that Iran is trying to establish a large-scale drone program in Syria, as part of efforts to expand its military presence there.

But alongside Russia’s protests to Israel over the fact it views both strikes as endangering its personnel, there is also apparently some tension between Russia and Iran. American intelligence sources say Iran even moved its people from T4 to a Syrian airbase near Palmyra, far away from the area where Russia operates, for several weeks. It’s possible the Russians threatened to stop arms shipments from Iran to Damascus if Iran didn’t do so.

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Nevertheless, Iran recently returned to T4 and continues to deploy its Revolutionary Guards elsewhere in central Syria, including near Damascus international airport. Israel believes all this has been done with Syrian President Bashar Assad’s knowledge and that he hasn’t tried to dissuade the Iranians from such activities, even though they put his own forces at risk.

Open gallery view The T-4 base, near Palmyra, that was attacked. Credit: Google / DigitalGlobe

Israel doesn’t yet have concrete evidence that Assad’s forces used chemical weapons to slaughter civilians in rebel-held Douma, near Damascus, last weekend. But it assigns high credibility to the claims there was a chemical attack and that Assad’s forces were responsible for it. There were reportedly two attacks at the site – one using chlorine and one using a nerve gas, possibly sarin.

An analysis of footage of the dead and wounded shows clearly that some were hit by nerve gas. Israel doesn’t believe the Syrian, Russian and Iranian claim that the rebels forged evidence of the attack, while the chance that the rebels themselves accidently used chemical weapons against civilians in an area under their control seems very slim.

Maintaining and using such weapons is relatively difficult, and the rebels in that area – the northern and eastern suburbs of Damascus – aren’t known to have such capabilities. In contrast, an Israeli Foreign Ministry statement denouncing the use of chemical weapons said the Assad regime recently resumed making such weapons.

The Syrian army has almost finished conquering the rebel enclaves in this area. The Syrians, backed by heavy Russian aerial bombardments, have mounted massive assaults on rebel-held neighborhoods to pressure them into signing surrender agreements.

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But for the first time in years, the Syrians aren’t noticeably relying on Shi’ite militias affiliated with Iran. Some of those militias have been assigned other tasks, including maintaining control of areas that have already been captured, like the northern city of Aleppo.

Open gallery view Israeli military forces in northern Golan Heights. Credit: Gil Eliahu

In contrast, Hezbollah’s elite units, including its Radwan commando force, are sent into battle whenever the Syrian effort runs into trouble. They are also assigned to protect assets vital to the regime in Damascus and the Alawite region in northwestern Syria. Hezbollah has a limited presence in southern Syria as well, and Israel suspects this is part of Iran’s future plans to create military friction with Israel along the border in the Golan Heights.

After they finish the fight in northern and eastern Damascus, Assad’s forces are expected to turn on the last major pocket of resistance near the capital: the Palestinian refugee camp of Yarmouk in southern Damascus. The Islamic State still maintains an active presence in this area.

Later, regime forces are expected to mount a major offensive in southern Syria – in Daraa, near the Jordanian border, and probably also in the Syrian part of the Golan, near Israel’s border.

Israel’s assumption is that the regime will make every effort to regain effective control of most of the Syrian Golan, and that its offensive, backed by Russia and Iran, will continue.