US troops in Syria came under direct attack from Turkish-backed forces

US troops fighting for the coalition against ISIS came under direct attack from the Turkish-backed Free Syrian Army in Northern Syria, multiple outlets are reporting.

"Our forces did receive fire and return fire and then moved to a secure location," US Army Col. Ryan Dillon told the Daily Sabah on Tuesday. "The coalition has told Turkey to tell the rebels it backs there that firing on U.S.-led coalition forces is not acceptable."

Sources told CNN that no casualties occurred on either side.

Turkey backs a number of forces that oppose Syrian President Bashar Assad and has made efforts to keep its border area clear of ISIS and other militants.

The US supports several Syrian militias that also oppose Assad, though the US now only supports them in their fight against ISIS. However it seems that the Turkish-allied forces likely knew they were exchanging fire with US soldiers.

"These patrols are overt. Our forces are clearly marked and we have been operating in that area for some time," Dillon told CNN. "It should not be news to anyone that we are doing this, operating in that particular area."