A drone attack by Iran-backed militias on a U.S. base in Syria's Deir el-Zour killed six terrorists of the PKK's Syrian offshoot YPG on Monday.

The drone struck a so-called commando academy of the U.S.-backed SDF at Al-Omar oilfield, Reuters reported, citing a spokesman for the terrorist YPG-dominated SDF.

An umbrella group of several Iran-backed Iraqi armed groups on Monday claimed responsibility for a drone attack on Al-Omar field, saying it launched the attack on Feb. 4.

Initial investigations confirmed that Iranian-backed militias operating in areas under the Assad regime control staged the attack, an SDF statement later said.

The U.S. Army frequently provides military training and supplies to members of the PKK/YPG terror group in bases located in the Mount Abdulaziz region of Hassakah as well as in the eastern Al-Omar oil field and Conoco area of Deir El-Zour province, all regions occupied by the terrorists, which Washington calls its "partner forces."

Despite Ankara’s documentation of the fact that the YPG and PKK are, in actuality, the same terrorist group, consistent U.S. support for the terrorists remains a source of significant strain between the allies.

Washington blames the group for a drone attack on a U.S. outpost in Jordan earlier this month that killed three U.S. forces. The U.S. launched dozens of strikes over the weekend against Iran-backed groups in Iraq and Syria, killing about 40 people, the vast majority reported to be militants.

Iran-backed groups declaring support for the Palestinians have entered the fray across the region as the war between Israel and the Hamas group has intensified.

Lebanese Hezbollah has fired at Israeli targets at the Lebanese-Israeli border, Iraqi militias have fired on U.S. forces in Iraq, Syria and Jordan, and the Houthis have fired on shipping in the Red Sea.