WASHINGTON -- The United States launched an airstrike in Syria on Thursday, targeting a facility near the Iraqi border used by Iranian-backed militia groups. The Pentagon said the strike was retaliation for a rocket attack in Iraq earlier this month that killed one civilian contractor and wounded a U.S. service member and other coalition troops.
The airstrike was the first military action undertaken by the Biden administration, which in its first weeks has emphasized its intent to put more focus on the challenges posed by China, even as Mideast threats persist. President Joe Biden's decision to attack in Syria did not appear to signal an intention to widen U.S. military involvement in the region but rather to demonstrate a will to defend U.S. troops in Iraq.
"I'm confident in the target that we went after, we know what we hit," Defense Secretary Lloyd Austin told reporters flying with him from California to Washington. Speaking shortly after the airstrike, he added, "We're confident that that target was being used by the same Shia militants that conducted the strikes," referring to a Feb. 15 rocket attack in northern Iraq that killed one civilian contractor and wounded a U.S. service member and other coalition personnel.
U.S. officials said the military response was essentially a tiny demonstration strike: one bomb dropped on a small cluster of buildings on the Syria-Iraq border used to transit militia in and out of the country.
The strike was just over the border in Syria to avoid diplomatic blowback to the Iraqi government. The Pentagon offered up several larger groups of targets but Biden approved the smallest option, U.S. officials said.
"We said a number of times that we will respond on our timeline," Austin said. "We wanted to be sure of the connectivity, and we wanted to be sure that we had the right targets."
Earlier, Pentagon spokesman John Kirby said the U.S. action was a "proportionate military response" taken together with diplomatic measures, including consultation with coalition partners.
"The operation sends an unambiguous message: President Biden will act to protect American and coalition personnel," Kirby said. "At the same time, we have acted in a deliberate manner that aims to de-escalate the overall situation in eastern Syria and Iraq."
Kirby said the U.S. airstrikes "destroyed multiple facilities at a border control point used by a number of Iranian-backed militant groups," including Kataib Hezbollah and Kataib Sayyid al-Shuhada. The U.S. has blamed Kataib Hezbollah for numerous attacks targeting U.S. personnel and interests in Iraq in the past.
Kirby said the American retaliation was meant to punish the perpetrators of the rocket attack but not to escalate hostilities with Iran, with which the Biden administration has sought to renew talks on a nuclear deal that President Donald Trump had shelved.
"We have acted in a deliberate manner that aims to de-escalate the overall situation in both eastern Syria and Iraq," Kirby said.
Biden authorized the strikes Thursday morning, as his defense secretary was at a hotel in San Diego, preparing to visit the aircraft carrier USS Nimitz, which was returning home from the Persian Gulf.
Further details were not immediately available.
Biden administration officials condemned the Feb. 15 rocket attack near the city of Irbil in Iraq's semi-autonomous Kurdish-run region, but as recently as this week officials indicated they had not determined for certain who carried it out. Officials have noted that in the past, Iranian-backed Shiite militia groups have been responsible for numerous rocket attacks that targeted U.S. personnel or facilities in Iraq.
Kirby had said Tuesday that Iraq is in charge of investigating the Feb. 15 attack.
"Right now, we're not able to give you a certain attribution as to who was behind these attacks, what groups, and I'm not going to get into the tactical details of every bit of weaponry used here," Kirby said. "Let's let the investigations complete and conclude, and then when we have more to say, we will."
A little-known Shiite militant group calling itself Saraya Awliya al-Dam, Arabic for Guardians of Blood Brigade, claimed responsibility for the Feb. 15 attack. A week later, a rocket attack in Baghdad's Green Zone appeared to target the U.S. Embassy compound, but no one was hurt.
Iran this week said it has no links to the Guardians of Blood Brigade.
The frequency of attacks by Shiite militia groups against U.S. targets in Iraq diminished late last year ahead of Biden's inauguration, though now Iran is pressing America to return to Tehran's 2015 nuclear deal.
The U.S. under the previous Trump administration blamed Iran-backed groups for carrying out the attacks. Tensions soared after a Washington-directed drone strike that killed top Iranian Gen. Qassem Soleimani and powerful Iraqi militia leader Abu Mahdi al-Muhandis last year.
The Biden administration has taken a more measured response to the rocket fusillade in Irbil than Trump's pitched campaign against Iran and past actions of its proxies in Iraq -- one that often caught the Iraqi government in the crossfire.
Administration officials have said since the Irbil attack that the United States would respond to the strike at a time and place of its choosing.
Even so, the deliberateness of the new administration's approach has raised questions both in Washington and in Baghdad about where Biden's red lines are when it comes to responding to attacks from Iranian-backed militias that target Americans in Iraq.
Trump had said the death of a U.S. contractor would be a red line and provoke U.S. escalation in Iraq. The December 2019 killing of a U.S. civilian contractor in a rocket attack in Kirkuk sparked a tit-for-tat fight on Iraqi soil that brought the country to the brink of a proxy war.
U.S. forces have been significantly reduced in Iraq to 2,500 personnel and no longer partake in combat missions with Iraqi forces in ongoing operations against the Islamic State group.
Information for this article was contributed by Lolita C. Baldor and Robert Burns of The Associated Press; and by Helene Cooper and Eric Schmitt of The New York Times.