Syrian state-run TV has slammed the US-led coalition attack on government's allied troops east of the Euphrates River as a "new aggression" and "an attempt to support terrorism".

"International coalition forces are bombing popular forces fighting "Daesh" and the [Syrian Democratic Forces] east of the Euphrates river and there are reports of casualties," statements carried by the stations said.

According to ABC citing sources, at least 100 pro-government forces have been killed in air and artillery strikes carried out by the US-led coalition in Syria. There were no US casualties in the attack on the headquarters, the media outlet claimed.

Earlier in the day, US Central Command announced that the coalition conducted defensive airstrikes against pro-government forces in Syria that attacked Syrian Democratic Forces headquarters near the Euphrates River.

"Syrian pro-regime forces initiated an unprovoked attack against well-established Syrian Democratic Forces headquarters Feb. 7," the release said. "In defense of Coalition and partner forces, the Coalition conducted strikes against attacking forces to repel the act of aggression against partners engaged in the Global Coalition's defeat-Daesh mission."

Damascus has yet to comment on the attack.

In this Monday, Nov. 6, 2017 photo, U.S. Marines prepare to build a military site during a sandstorm in western Anbar, Iraq. The US-led coalition's newest outpost in the fight against the Islamic State group is in this dusty corner of western Iraq near the border with Syria where several hundred American Marines operate close to the battlefront, a key factor in the recent series of swift victories against the extremists.

The Pentagon has been providing the Kurdish-dominated Syrian Democratic Forces with weapons, saying recently, however, that the weapons were provided for use in Syria's Raqqa to retake it from IS.

Earlier, the Defense Post news website reported that the US-led coalition was training a force on Syrian territory controlled by the SDF to maintain border security, which has drawn sharp criticism from Ankara.

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