The attack expands on a series of retaliatory attacks as Israel's war in Gaza threatens to escalate across the region.
An overnight drone attack on a US military base in eastern Syria killed several Kurdish-led fighters.
The UK-based Syrian Observatory for Human Rights (SOHR) said on Monday that seven fighters had been killed and at least 18 wounded.
The attack follows U.S. strikes on targets in Iraq and Syria over the weekend. Insurgents allied with Iran have also announced attacks on U.S. military bases in Syria, western and northern Iraq, amid a smoldering low-level war with the United States.
The Observatory said of Monday's incident, “The attack was carried out as the first response by Iranian militias to a US military base after the US military carried out airstrikes on militia positions in various areas within the territory it controlled. ” he said.
SOHR added that since October 19, “108 attacks” have been carried out against US-led Joint Task Force bases across Syria. The US-led coalition was established in 2014 to fight ISIL (ISIS).
The Syrian Democratic Forces (SDF) announced another death toll, saying that “six fighters were martyred” in a one-way drone attack targeting a training school in the Al-Omar oil field.
The extended series of attacks signals a growing threat that Israeli airstrikes in Gaza risk triggering regional escalation across the Middle East.
The stakes increased dramatically late last month when a drone crashed into a U.S. military base in Jordan, killing three soldiers and injuring more than 40 others. The US government blamed Iranian-backed forces for the attack and vowed retaliation over the weekend.
US forces attacked Tehran-backed groups in Iraq and Syria on Friday and Saturday. US and British forces launched attacks on 36 Houthi targets in Yemen on Sunday.
The U.S. military's Central Command (CENTCOM) said its forces “conducted a self-defense attack against Houthi ground-attack cruise missiles” and subsequently “hit four anti-ship cruise missiles, all of which hit ships in the area.” “We were ready to fire against them,” he said. Red Sea”.
February 4th Overview of USCENTCOM’s additional self-defense strikes in Yemen
At approximately 5:30 a.m. (Sanaa time) on February 4, U.S. Central Command conducted a self-defense strike against a Houthi ground-attack cruise missile.
U.S. forces attacked from 10:30 a.m. pic.twitter.com/ScZWEajJe2
— U.S. Central Command (@CENTCOM) February 5, 2024
The U.S. government has said it plans further military action, but has sought to ensure it does not want to escalate risks in the region.
White House national security adviser Jake Sullivan told national television on Sunday that Friday's airstrike was “the beginning, not the end, of our response, and that there will be more steps, some visible, some likely… There may be things you can't see.”
“I would not call this an open-ended military operation,” he added.
The Pentagon has also said it does not want war with Iran.
Iran has so far avoided any direct role in the Gaza conflict and its aftermath, despite its alliance with groups opposed to the United States.
The Iran-backed Houthis, who have been attacking ships in the Red Sea for months in solidarity with Palestinians in the Gaza Strip, said on Sunday that U.S. and British attacks would not defeat them.
“These attacks do not deter us from supporting the determined Palestinian people of the Gaza Strip,” Houthi military spokesman Yahya Salih said on social media. He added that the strike “will not stand without response and punishment.”