Syrian civlians flee from the regime air strikes on the  outskirts of Damascus. PIC/AFP

The US-led coalition killed at least 100 regime and allied fighters in retaliation for an attack in eastern Syria, a US official said, in one of the deadliest incidents of its kind. The flare-up lasted into the small hours of Thursday and was sparked by an attack on positions held by the Kurdish-led Syrian Democratic Forces (SDF) in Deir Ezzor province.