Drone attacks have wounded six U.S. service members and killed a Defense Department contractor, and the new explosive devices could add to the toll of U.S. casualties, risking a wider military confrontation with Iran, current and former intelligence analysts and weapons experts say. The same type of weapon, called an explosively formed penetrator, or EFP, was used by pro-Iranian insurgents in lethal attacks against American military convoys during the U.S. occupation of Iraq.
Officials with Iran’s elite Quds Force unit directed and oversaw testing of one of the explosives, which reportedly sliced through a tank’s armored plating in a trial run conducted in late January in Dumayr, east of Damascus, the Syrian capital, according to one of the intelligence reports. The document, part of the trove of classified materials leaked on the messaging platform Discord, appears to be based on intercepted communications by Syrian and Lebanese militants allied to Iran. One apparent attempt to use such devices against U.S. forces was apparently thwarted in late February when three bombs were seized by U.S.-allied Kurdish fighters in northeastern Syria, a second document states.
“There has been a sea change in their risk-acceptance in killing Americans in Syria,” said Michael Knights, an expert on Iranian-backed militia groups and a founder of the website Militia Spotlight. Noting the devastating toll exacted by EFP bombs during the Iraq War, he added: “This will definitely kill people. And they’re thinking very hard about how to do it.”
Another document in the trove describes a new and broader effort by Moscow, Damascus and Tehran to oust the United States from Syria, a long-sought goal that could allow Syrian President Bashar al-Assad to reclaim eastern provinces now controlled by U.S.-backed Kurdish forces. The past three U.S. administrations have maintained a small contingent of U.S. troops in Syria — about 900 at any given time, augmented by hundreds more contractors — to prevent a resurgence by Islamic State militants in the country, thwart Iranian and Russian ambitions, and provide leverage for other strategic objectives.
U.S. administrations have justified the deployment under the 2001 and 2002 Authorizations for Use of Military Force, which Congress passed in the wake of the Sept. 11, 2001, terrorist attacks to fight al-Qaeda. But the presence of U.S. troops in Syria also creates opportunities for new conflict: Another document in the trove describes how Iran and allied militias were preparing to retaliate for Israeli strikes on their forces by hitting U.S. bases in Syria.
The leaked documents describe plans for a wide-ranging campaign by U.S. opponents that would involve stoking popular resistance and supporting a grass-roots movement to carry out attacks against Americans in eastern and northeastern Syria. High-ranking Russian, Iranian and Syrian military and intelligence officials met in November 2022 and agreed on establishing a “coordination center” for directing the campaign, according to a classified intelligence assessment prepared in January.
There were no indications in the documents of direct Russian involvement in planning the bombing campaign. But the leaked documents point to a more active role by Moscow in the broader anti-U.S. effort. Russia, like Iran, intervened militarily in Syria’s civil war to keep the Assad regime in power and now backs the government’s efforts to regain control of the entire country. In the months since the leaked documents were written, Russia has engaged in new provocations against U.S. forces, including violating deconfliction agreements, flying over U.S. bases and buzzing U.S. aircraft.
While it has been long-standing Russian policy to eject the United States from Syria, the creation of a joint coordination center to achieve that goal is new, said Aaron Stein, a senior fellow at the Foreign Policy Research Institute. In the event that attacks by militia groups were to kill U.S. forces, Iran and Russia probably believe they can manage the escalation, because the U.S. military would probably limit its response to strikes against targets inside Syria, the default retaliation under both the Trump and Biden administrations, Stein said.
But he cautioned that Russia’s invasion of Ukraine and the collapse of the 2015 Iran nuclear deal made the situation more volatile and harder to predict, and that domestic U.S. political dynamics might make it harder to been seen as backing down against Russia.
The new active planning reflected in the leaked documents means “there’s a good chance things could escalate,” said Mohammed Ghanem, the head of policy at the Syrian American Council and an opponent of the Assad regime.
EFPs are more sophisticated variants of roadside bombs — commonly known as improvised explosive devices, or IEDs — that became a hallmark of the insurgent campaign against U.S. forces in Iraq after the 2003 invasion. The devices are typically triggered by remote sensors and use a “shaped” explosive charge to hurl a slug of molten metal toward a target at high velocity.
One of the leaked documents describes attempts by a bombmaker with Lebanon’s Hezbollah militia group, which is allied with Iran, to carry out tests on a new type of EFP in Syria in late January. The device, measuring just under five inches in diameter, was assessed to be both powerful and “concealable” due to its small size and payload of 3.3 pounds of C-4 military explosive. In two tests, the bomb’s projectile was able to penetrate nearly three-inch-thick tank armor at a range of about 75 feet, the document said. A third test failed, the document said.
The report said officials with the Quds Force, an elite unit of Iran’s Islamic Revolutionary Guard Corps, assisted with the bomb’s design and operational advice on its use. A Quds Force official named Sadegh Omidzadeh specifically “identified U.S. Humvee and Cougar armored vehicles in Syria” as the intended targets and spoke of dispatching unidentified operatives to take reconnaissance photos of roads traveled by U.S. forces, the document said.
A separate document that described how Kurdish fighters seized three EFPs said the devices were being transported by a Syrian Quds Force “associate” in preparation for an “eventual attack on U.S. forces” near Rumeilan in northeastern Syria.
The Pentagon has declined to comment on the leaked documents and did not respond to questions about the intelligence detailing the new plots against U.S. forces in Syria. But the move by Iranian-backed militias to escalate attacks against Americans with roadside bombs was confirmed in interviews with two current officials and one former official with access to sensitive intelligence from the region. Some independent analysts said Iran’s increasingly aggressive behavior suggests that Tehran has — or believes it has — Russia’s tacit support for ratcheting up the pressure campaign. Moscow has come to depend on its Iranian ally as a principal supplier of drones and other weapons for its military assault against Ukraine.
“One outcome of Iran’s increasingly close military ties with Russia is a freer hand in Syria,” said Farzin Nadimi, an Iran specialist and senior fellow at the Washington Institute for Near East Policy, a Washington think tank. “Now that Iran might actually have received this green light from the Russians, they want to gradually up their game.”
The new resistance campaign is likely to find fertile ground in Arab-majority areas that chafe at the presence of U.S. forces and rule by the Kurdish autonomous authority that controls large swaths of Syria’s east and northeast, experts said. Local competition for power and a “messy, angry environment” create an ideal climate to stir up unrest and organize militant groups, said Aron Lund, a fellow at the think tank Century International.
Russia has emerged from the 12-year-old Syrian war as the region’s principal power broker, having rescued the Assad regime, and now presides over a shaky and complicated stalemate. While Moscow shares Syria’s goal of ultimately ejecting U.S. forces and wants to reconcile the Assad regime with Turkey and the Syrian Democratic Forces — the Kurdish armed group that runs the autonomous east — it does not share Turkey’s ambition of eliminating Kurdish control by force, which could cause chaos and an Islamic State resurgence, Lund said.
Although Russia’s alliance with Tehran has strengthened since the start of the Ukraine conflict, Russian and Iranian leaders have conflicting ideas about the postwar administration of Syria, and Russia has tacitly allowed Israel to carry out airstrikes against perceived Iranian threats inside Syria. One leaked document states that Russia’s “transactional” relationship with Iran has been a source of friction between the two governments, and that Iran has repeatedly complained about being excluded from Russian-led negotiations with Turkey over a proposed permanent settlement to the conflict.