Updated March 24, 2023 at 5:31 PM ET
U.S. forces in eastern Syria were targeted in a rocket attack Friday morning, in tit-for-tat strikes between the U.S. and militia groups supported by Iran, the Pentagon said.
In the attack, "10 rockets targeted coalition forces at the Green Village in northeast Syria," U.S. Central Command said in a news release issued Friday.
The strike did not cause damages or injuries to U.S. forces or their partners, the command said. But it added that one rocket landed nearly five kilometers off-target, "striking a civilian house, causing significant damage and causing minor injuries to two women and two children."
Thursday's drone attack left 1 dead
The latest incident came just a day after a militia drone strike killed a U.S. contractor, injured five American service members and wounded one other contractor in Syria, the Defense Department said.
Intelligence sources say the drone, which struck a U.S. base near Hasakah, was made by Iran, Defense Secretary Lloyd Austin said in a statement.
The drone in Thursday's deadly attack struck a maintenance facility at the base around 1:38 p.m. local time, Brig. Gen. Pat Ryder, the Pentagon press secretary, said at a news briefing Friday.
"It did not fire a weapon, to my knowledge," he said.
Asked on Friday how the drone was able to penetrate the site's defenses, Ryder refused to go into detail about the protections. He added, "My understanding is that there was a complete site picture in terms of radar."
The U.S. used F-15 fighter jets to retaliate
In response, the U.S. Central Command conducted "precision airstrikes" on groups it says were connected with Iran's Revolutionary Guard Corps.
"As President Biden has made clear, we will take all necessary measures to defend our people and will always respond at a time and place of our choosing," Austin said. "No group will strike our troops with impunity."
Videos shared on social media showed explosions in Deir el-Zour, a Syrian province near the Iraq border that contains oil fields.
That area is controlled by Iran-backed militia groups and Syrian forces, according to the Associated Press, and has seen recent damage from suspected airstrikes by Israel, targeting alleged Iranian supply routes.
In the U.S. strikes, Ryder said two Air Force F-15 fighter jets struck two Islamic Revolutionary Guard Corps-affiliated facilities at around 2:40 a.m. local time.
"Initial indications are that the facilities were destroyed," he said, adding that the U.S. is still assessing any potential militant casualties.
The U.S. strikes on Thursday killed 11 people, according to the Syrian Observatory for Human Rights, a group that monitors violence in the region with a network of local sources. Six were Iranian-backed militants in a warehouse in the city. Two were killed on the outskirts of a surrounding town, Al-Mayadeen. Three others were killed in the surrounding desert.
"The number of fatalities is expected to rise, as the strikes left several militiamen injured, some seriously," the group wrote online.
Neither Iran nor Syria appeared to immediately acknowledge the strikes.
Speaking at a joint news conference in Ottawa with Canadian Prime Minister Justin Trudeau, President Biden said Friday: "To make no mistake, the United States does not — does not, emphasize — seek conflict with Iran, but be prepared for us to act forcefully to protect our people. That's exactly what happened last night."
Ryder made similar remarks, saying: "We do not seek conflict with Iran. We don't seek escalation with Iran. But the strikes that we took last night were intended to send a very clear message that we will take the protection of our personnel seriously, and that we will respond quickly and decisively if they are threatened."
Renewed violence imperils de-escalation attempts
The attack and retaliation pose threats to recent negotiations aimed at de-escalating tensions across the Middle East. Earlier this month, Iran and Saudi Arabia agreed to restore diplomatic ties in a deal brokered by China, raising questions about whether U.S. influence in the region is at risk of being overshadowed.
The U.S. has had ground troops in northeastern Syria since 2015 when it was fighting the Islamic State.
Syria's civil war, which erupted in 2011, has morphed into a wider proxy conflict that includes U.S. forces supporting Kurdish fighters, and Iran supporting militants.
Austin said that Thursday's retaliatory airstrikes were not just a response to the most recent drone strike, but also to a "series of recent attacks against coalition forces in Syria."
Iran's Revolutionary Guard has launched an estimated 78 attacks on U.S. forces in Syria since January 2021, U.S. Army General Michael "Erik" Kurilla, who heads Central Command, told the U.S. House Armed Services Committee on Thursday.
The U.S. Central Command, which was formed in 1983 to monitor Iranian expansion, has raised alarm about the expansion of the Iran's military strength.
The country's Islamic Revolutionary Guard Corps, a paramilitary group that reports to Supreme Leader Ali Khamenei, relies on proxy militia groups throughout the region.
In written comments to the U.S. House committee, Kurilla said that deterring Iran is "arguably more urgent than at any time in CENTCOM's history" because the IRGC is able to arm those proxy groups with increasingly sophisticated weapons like uncrewed drones, as well as ballistic and cruise missiles.
Iran has sold advanced drones to other nations, including Russia for use against Ukraine.
"Iran possesses the largest and most diverse missile arsenal in the Middle East," Kurilla said. "Even more concerning, Iran has advanced its nuclear program such that Tehran can now produce sufficient fissile material for a nuclear weapon in less than 14 days."
Talks about reviving the 2015 Iran Nuclear Agreement, which former President Donald Trump abandoned in 2018, continue to stall.
In a statement following Thursday's airstrikes, Kurilla said the Army was "postured for scalable options in the face of any additional Iranian attacks."
"We will always take all necessary measures to defend our people," he wrote.
Two of the service members were treated on site, the Pentagon said. Three others were medically evacuated to medical facilities in Iraq.
NPR's Peter Kenyon and Andrew Sussman contributing reporting.
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