Coalition hits back over reported civilian deaths in east Syria

The US-led anti-jihadist coalition hit back Sunday at reports its air strikes on an Islamic State group holdout in eastern Syria had killed civilians, appearing to blame their deaths on regime forces.

More than seven years into the country's civil war, multiple offensives have whittled down the swathes of Syrian territory IS once controlled to a small pocket in the eastern province of Deir Ezzor on the Iraqi border.

A Kurdish-led alliance backed by the coalition is battling to expel IS from that holdout, on the eastern bank of the Euphrates.

Russian-backed regime forces have been fighting the jihadists west of the river.

The Syrian Observatory for Human Rights said coalition strikes on Saturday killed 43 people, including 36 family members of IS fighters in the village of Abu al-Husn.

But the coalition denied that its air raids there had killed any non-combatants.

The US envoy for the coalition, Brett McGurk on Sunday appeared to blame regime forces stationed "across the river" for the civilian casualties.

"Reports of civilian casualties attributed to coalition strikes are false. All other forces should cease uncoordinated fires from across the river immediately," he said on Twitter.

In a statement late Saturday, the coalition reported 19 coalition strikes on IS targets "free of civilian presence" between late Friday and Saturday afternoon in the jihadist enclave, which includes the town of Hajin.

The coalition's "initial assessment following the strikes is that there was no evidence of civilians near the strikes", it said.

But the coalition "detected a total of ten additional strikes in the same area of Hajin that did not originate from the coalition or partner forces," it added.

It called "on all other actors to cease uncoordinated fires across the Euphrates."