The U.S. military bombed a site in Syria on Friday, targeting facilities near the Iraqi border used by Iranian-backed militia groups, BBC and Axios reported on Saturday.
The Pentagon said the airstrikes were retaliation to rocket attacks on U.S. troops in the region in the past two weeks that killed one civilian contractor and wounded an American service member and other coalition forces.
It was the first known military action carried out by the Biden administration, which during its first weeks has underscored its intent to put more focus on the challenges posed by China, even as threats in the Middle East persist.
U.S. military officials said the strike destroyed "multiple facilities." Militia officials said one person was killed but a war monitor reported at least 22 fatalities.
The attack swiftly drew criticism from Democratic legislators. Syria condemned the strikes as a "bad sign" from the new U.S. administration.
Nearly a day later, Iran's foreign ministry denounced the attack. Saeed Khatibzadeh, ministry spokesperson, called the strikes a "continuation of Zionist regime raids on Syrian soil," a reference to Israeli aerial attacks on Syria.
"This proportionate military response was made together with diplomatic measures, including consultation with coalition partners," the Associated Press quoted the Pentagon's chief spokesperson, John Kirby, as saying in announcing the strikes.
There are around 2,500 American troops in Iraq to assist the country's soldiers in the fight against the Islamic State group.
"President Biden will act to protect American and coalition personnel. At the same time, we have acted in a deliberate manner that aims to de-escalate the overall situation in both Iraq and eastern Syria," the Pentagon said in a statement quoted by BBC.
When asked by a journalist what message he wanted to send to Iran with his administration's first military action, Biden said, "You can't act with impunity. Be careful."
