Crossing the Euphrates: In its fight against the "Islamic State" (IS) group the Syrian army has rarely clashed with SDF forces in the area. The predominantly Kurdish alliance seized much of the territory east of the Euphrates River in Deir el-Zour province during a campaign to drive out IS, but they have mostly stayed on their respective sides of the river. In February an attack on US personnel and SDF forces led to US airstrikes killing at least 100 pro-regime fighters.
Sabotage: On Sunday, the SDF accused Syrian authorities of attempting to disrupt US plans to resume an imminent offensive against IS in the area.
"We affirm that we are determined to eradicate terrorism from its roots and to assert our right to self-defense," SDF spokesman Kino Gabriel said about IS. "We consider this aggression by regime forces to be a support for terrorism and falls within the attempts to impede the war on terrorism."
IS expelled: IS once held a large part of Deir el-Zour province, but over the past year regime forces recaptured most areas west of the Euphrates while SDF fighters took areas east of the river.