Updated

A drone attack late Sunday evening that struck a military base in eastern Syria, where U.S. troops are stationed, left at least six allied Kurdish soldiers dead, officials said.

The attack hit a training ground at al-Omar base in Syria’s eastern province of Deir el-Zour, the U.S.-backed, Kurdish-led Syrian Democratic Forces (SDF) said in a statement Monday. According to the statement, the drone attack struck an area where the forces' commando units were being trained.

No U.S. troops were killed or injured in the attack, they said.

The strike was the first significant attack in Syria or Iraq since the U.S. launched strikes over the weekend against Iran-backed militias. Militia fighters have been carrying out assaults on U.S. forces and civilian targets in the region since the breakout of the Israel-Hamas war in October.

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A parked fighter jet

This photo issued by the Ministry of Defence on Sunday, Feb. 4, 2024, shows an RAF Typhoon FGR4 aircraft returning to the base, following strikes against Houthi targets in Yemen. (AS1 Leah Jones/RAF via AP)

The SDF initially blamed "Syrian regime-backed mercenaries" for Sunday's attack, but after investigating the attack, they accused "Iran-backed militias."

The Islamic Resistance, an umbrella group of all Iran-backed Iraqi militias in the country, claimed responsibility for Sunday's attack and released a video they claim showed them launching the drone used in the attack.

Map shows attacks on US forces in the Middle East since Oct. 17

A map shows there have been at least 168 attacks on U.S. forces in the Middle East since Oct. 17, 2023, as of Feb. 5, 2024. (Fox News)

Sunday’s attack came after the U.S. military carried out strikes against Houthi militant targets in Yemen over the weekend.

U.S. Central Command forces said Sunday they conducted a "self-defense" strike against a Houthi land attack cruise missile at approximately 5:30 a.m. Sanaa time.

Later, at approximately 10:30 a.m., U.S. forces struck four anti-ship cruise missiles in Houthi-controlled areas of Yemen, which they determined "presented an imminent threat to U.S. Navy ships and merchant vessels" in the Red Sea.

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Sunday’s strikes also came a day after the U.S. and Britain launched a wave of strikes against 36 Houthi targets, meant to degrade their capabilities.

Soldier standing next to a plane

The U.S. and Great Britain struck 36 Houthi sites in Yemen in a second wave of assaults meant to further disable Iran-backed groups that have relentlessly attacked American and international interests in the wake of the Israel-Hamas war. (AS1 Jake Green/RAF via AP)

Houthi rebels vowed "escalation" in reaction to the strikes, with a spokesman for the group vowing to continue its own attacks "no matter the sacrifices it costs us."

"The US-British coalition’s bombing of a number of Yemeni provinces will not change our position, and we affirm that our military operations against Israel will continue until the crimes of genocide in Gaza are stopped and the siege on its residents is lifted, no matter the sacrifices it costs us," Houthi spokesman Mohammed al-Bukhaiti wrote on X.

The Houthi spokesman also called such attacks "ineffective," and predicted a wider war would end the U.S. presence in the region.

"If the regional war breaks out, it equals the end of US hegemony in the region," he said.

The Islamic Resistance was responsible for the January drone attack on Tower 22 of the logistics support base in Jordan that left three U.S. service members dead and wounded 40 others.

A plane in a hangar

In addition to the strikes on Saturday, U.S. Central Command says it conducted an additional "self-defense" strike on Sunday against a Houthi anti-ship cruise missile. (AS1 Jake Green/RAF via AP)

The U.S. Defense Department identified the three deceased soldiers as Sgt. William Jerome Rivers of Carrollton, Georgia; Spc. Kennedy Ladon Sanders of Waycross, Georgia; and Spc. Breonna Alexsondria Moffett of Savannah, Georgia.

They were assigned to the 718th Engineer Company, 926th Engineer Battalion, 926th Engineer Brigade, Fort Moore, Georgia.

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"I am outraged and deeply saddened by the deaths of three of our U.S. service members and the wounding of other American troops in an attack last night against U.S. and coalition forces, who were deployed to a site in northeastern Jordan near the Syrian border to work for the lasting defeat of ISIS," Defense Secretary Lloyd Austin said after the attack. "These brave Americans and their families are in my prayers, and the entire Department of Defense mourns their loss."

The umbrella group has launched dozens of attacks, primarily using drones, against U.S. military bases in Iraq and Syria. They have repeatedly called for American forces to withdraw from the region.

Fox News' Anders Hagstrom, Liz Friden and The Associated Press contributed to this report.