U.S.-led coalition says it struck Syrian pro-regime forces

The US-led coalition in Syria responded to an attack by Syrian pro-regime forces on February 7, according to a statement from the Combined Joint Task Force, Operation Inherent Resolve.
"Syrian pro-regime forces initiated an unprovoked attack against well-established Syrian Democratic Forces Headquarters," the statement says. Coalition service members who were advising the SDF and accompanying them were in the vicinity of the attack which happened eight kilometers east of the "agreed-upon Euphrates River de-confliction line."
The Euphrates River de-confliction line is a line the coalition and the Syrian regime agreed on and which their forces are not supposed to cross so as to prevent any conflicts.
With the defeat of Islamic State in most of Syria the coalition and the Syrian regime share a long "de-confliction" line mostly along the Euphrates river.
After the attack the coalition "conducted strikes against attacking forces to repel the act of aggression."
The coalition has warned over the past year against any attacks on its SDF partners. In June 2017 the US shot down a Syrian jet after clashes near Tabqah.