Scores IS Syria fighters killed in group's last stand
At least 65 IS fighters were killed around their last enclave in eastern Syria following heavy air strikes this week, according to the Syrian Observatory for Human Rights.
The losses come despite a Kurdish-led assault on the militants was put on hold, in protest at Turkish shelling of Kurdish positions along Syria's northern border.
Waves of US-led air strikes since Monday killed 48 IS militants, including during two IS assaults on oilfields north of the Hajin enclave, the monitor said.
On Tuesday, IS launched an assault on the Azrak oil field, followed by an attack Wednesday on the Tanak oil field where US-backed SDF fighters are based, it said.
This led SDF fighters to kill 17 militants while defending a base in the village of al-Bahra, just outside IS-held territory on Monday.
Kino Gabriel, spokesperson for the group, said the pause in offensive operations did not mean SDF fighters would not defend themselves.
The SDF launched its assault on the IS enclave around the Euphrates valley town of Hajin, in Deir az-Zour, on 10 September.
Last month, IS used cover provided by sand storms to launch a series of counter-attacks had recaptured all of the territory the SDF had won.
The Hajin enclave is the last significant remnant of the "caliphate" IS proclaimed in 2014 across a vast swathe of Syria and neighbouring Iraq.
The rest has all been lost to offensives by multiple alliances on both sides of the border.
The group still carries out attacks by sleeper cells and has hideouts in unpopulated desert and mountain areas.