Militias backed by Iran’s Revolutionary Guards force attacked a U.S. military base in southern Syria with drones recently and on the same day, a different base used by the U.S.-led coalition near Syria’s eastern border with Iraq came under rocket fire.
U.S. officials saw the back-to-back strikes on Aug. 15 as more sophisticated than previous attacks and feared that more were coming. That set off a string of tit-for-tat attacks this week — including U.S. airstrikes on three consecutive nights against Iran-linked targets in Syria. They amplified tensions between two powerful adversaries fighting on a foreign battlefield.
The Americans made clear to Iran, through private channels as well as publicly, that they were not trying to escalate hostilities but only sought to protect U.S. interests, said a U.S. official who spoke on the condition of anonymity to discuss sensitive security matters.
The flare-up was a reminder of how Syria, fractured and weakened by more than a decade of civil war, has provided a fertile ground for a multitude of proxy wars to play out involving Iran, Israel, the United States, Russia, Turkey and the Islamic State, among other actors. The U.S. military presence — roughly 900 service members — in Syria makes it a potential target of choice for those players looking to vent their grievances with Washington or its close ally, Israel.
Senior U.S. officials said the Aug. 15 attacks on the two U.S. bases in Syria could have been an Iranian attempt to avenge a previous Israeli attack by targeting Israel’s U.S. allies. But Iran denied any connection to the groups in Syria.
The drone attack, on the U.S. base at al-Tanf, near the border in south Syria, came a day after Israel struck military targets in the Syrian provinces of Damascus and Tartus, killing three Syrian soldiers. Those strikes targeted a Syrian army air defense base where Iran-backed fighters are often stationed, according to the British-based monitoring group Syrian Observatory for Human Rights.
The new fighting comes at a very delicate moment in U.S.-Iran relations, as both sides are moving closer to agreeing on a revived nuclear deal that would lift sanctions on Iran in return for limits on its nuclear activities. Given that, any attacks that cause a large number of casualties on either side risk throwing the nuclear negotiations off course.
However, U.S. officials insisted there is no connection between the strikes in Syria and the nuclear negotiations. Other observers have wondered whether the attacks by forces allied with Tehran could be an effort by Iranian hard-liners to disrupt any deal.
Some Iranian analysts said they viewed the U.S. attacks as the Biden administration’s attempt to appease critics of the nuclear deal and demonstrate that it will maintain a tough stance against Iran even if a nuclear deal is reached.
The Islamic Revolutionary Guards Corps is a powerful arm of Iran’s armed forces that operates in parallel with the military. It is tasked with securing Iran’s borders, and its overseas branch, the Quds forces, carry out operations across the Middle East and beyond and train and arm Shiite proxy militias that operate in a number of countries. The U.S. has designated it as a terrorist group, which became a point of contention in the negotiations to revive the nuclear deal.
A senior U.S. official said there are several possible motives for Iran’s Aug. 15 attack. It could be a response to an Israeli strike or a new commander, said the official, who requested anonymity to discuss sensitive security issues. But the use of drones pointed clearly to the involvement of the Revolutionary Guards.
Iran has built increasingly sophisticated weapons-capable drones in recent years. It has both sold them commercially to other nations and stepped up their transfer to proxy groups.
The advancement of Iran’s drone capabilities, as well as their use in Arab states and against oil facilities in the United Arab Emirates and Saudi Arabia, has helped lead to a military partnership between Israel, several Arab militaries and the United States.
About a year ago, an Iranian-led alliance opposed to Israel met virtually to discuss how to respond to increasing Israeli attacks inside Syria, according to Gheis Ghoreishi, an analyst close to Iran’s government with knowledge of the Revolutionary Guards’ strategy in the region. It brought together military experts from Syria, Iraq, the Lebanese militant group Hezbollah, Yemen and Iran’s Quds forces — the overseas arm of the Revolutionary Guards.
A person in the Syrian capital, Damascus, who is close to the Iranian forces there, confirmed that the meeting took place, speaking on condition of anonymity because the person was not authorized to speak publicly.
During their discussions, the Syrians said they did not want attacks against Israel to be launched from their territory so as not to risk an all-out war at a time when the country is already weakened. So the alliance decided instead to retaliate for the Israeli strikes by hitting American bases in Syria, hoping that Washington would then pressure Israel to back off Iran.
For years, Israel and Iran have fought a clandestine war across the Middle East, and limited tit-for-tat attacks have recently escalated and expanded to include strikes on land, in the air and most recently, at sea.
The military experts at the meeting also concluded that although the U.S. military out-powered the proxy groups in Syria and would likely counterattack, the Biden administration policy was aimed at defusing tensions in the region and it sought to avoid starting any new war at a time when Washington’s attention was shifting away from the Middle East.
The meeting participants decided that for each Israeli strike on an Iranian target in Syria, there would be a retaliatory strike against a U.S. base there, and particularly al-Tanf.
“Iran’s focus on al-Tanf is because they consider it a troublesome spot for them,” said Omar Abu Layla, executive director of Deir Ezzor 24, a news and analysis organization that focuses on Syria’s eastern province of Deir al-Zour. “They want to expand their military influence on that area entirely.”
Drone and rocket attacks on U.S. military bases in Syria have recently gained pace.
Last year in October, Iranian proxy forces launched five drones loaded with ball bearings and shrapnel at al-Tanf base. American and Israeli officials at the time said the drone attack was the first time Iran had directed a strike against the U.S. in response to an attack by Israel.
Iran did not claim responsibility for the drone strike, but a Telegram channel run by affiliates of the Revolutionary Guards said it was in response to the U.S. allowing Israeli attacks on Iranian-allied forces in eastern Syria.
Iran’s involvement in Syria and the Revolutionary Guards presence dates back to 2011, when the Guards sent fighters and generals to help Syrian President Bashar al-Assad crush the 2011 Arab Spring uprising and prevail in the prolonged civil war that grew out of the revolt.
With Mr. Assad having emerged from more than a decade of conflict largely victorious and in control of most of the country, Iranian forces and tens of thousands of its proxy fighters from countries like Iraq, Lebanon and Afghanistan have remained in Syria as part of a broader regional policy of maintaining a threat to Israel in a state that shares a border.
“Iran’s winning card is that it now neighbors Israel through Syria as well,” said Mr. Ghoreishi.
Since then, Iran and its proxies have entrenched themselves in parts of Syria, especially in the east and around the capital, Damascus. They have built military infrastructure, bought real estate, recruited local fighters and attempted to spread Shiite Islam there.
U.S. officials said there are a relatively small number of Revolutionary Guards commanders remaining in Syria, running the allied militias made up of Syrian, Iraqi or Afghan fighters.
The U.S. strikes this week began on Tuesday night when fighter jets dropped guided bombs on about a dozen ammunition depots used by militant groups affiliated with the Revolutionary Guards in Deir al-Zour. U.S. officials said they didn’t want to spark a tit-for-tat escalation, so they made sure there were no militants at the depots when they struck to reduce the risk of casualties.
But the next day, a militia overseen by the Revolutionary Guards retaliated by attacking two U.S. outposts in Syria—Mission Support Site Conoco in northeast Syria and Green Village.
The U.S. military responded with AC-130 gunships and Apache attack helicopters, killing four militants.
“Now we believe, based on the intelligence, that we’ve re-established deterrence” said Col. Joseph Buccino, a spokesman for the U.S. Central Command. “We believe this back and forth has culminated.”
Farnaz Fassihireported from New York, Raja Abdulrahim from Beirut and Adam Entous from Washington.Hwaida Saadcontributed reporting from Beirut.