BEIRUT: Members of ISIS have 'executed' 19 civilians including two children in a village held by anti-extremists in eastern Syria, the Syrian Observatory for Human Rights said Saturday.

"ISIS fighters entered Jazrat al-Boushams village Friday evening and executed 19 civilians, including two women and two children, with bullets to the head before torching the corpses," Rami Abdel Rahman of the Britain-based activist group told AFP.

"Some were rounded up in the street before being killed, and others were executed at home," said the head of the Observatory, which gathers its information from a large network of sources across the war-torn country.

He said the extremists also abducted three members of the U.S.-backed anti-ISIS Kurdish-Arab Syrian Democratic Forces alliance (SDF) before withdrawing from the village.

Jazrat al-Boushams village is in Deir Ezzor province, which is largely controlled by the extremists.

It was captured by the SDF when alliance fighters first entered the region earlier this year.

The village is also near the neighboring province of Raqa, which ISIS mostly controls.

In November last year, the SDF began an offensive aimed at taking the city of Raqa, ISIS' de facto Syrian capital.

Despite being pressed militarily on all sides in Syria, notably by the SDF, the extremist group retains an ability to carry out murderous attacks.

On Thursday, ISIS killed more than 50 people in an assault on two government-held villages in central Syria's Hama province.

A day later, U.S. Defense Secretary Jim Mattis said President Donald Trump had instructed the Pentagon to "annihilate" ISIS in Syria in a bid to prevent escaped foreign fighters from returning home.