US-backed Syrian Democratic Forces fighters celebrate after fighting ISIS extremists near the village of Baghouz on March 15, 2019.

:: US-backed forces battled ISIS fighters overnight as the extremists clung onto their crumbling bastion in eastern Syria on Saturday.

“Clashes broke out again last night and have continued since,” said Adnane Afrine, spokesman for the Kurdish-led Syrian Democratic Forces (SDF).

“There have so far been no surrenders (today) and there’s no sign they are giving up,” he told AFP.

At an SDF post inside Baghouz village, the last ISIS redoubt, AFP journalists heard sporadic rounds of mortar fire and US-led coalition planes overhead.

ISIS launched three suicide attacks on Friday outside Baghouz, killing six people among those fleeing the crumbling extremist bastion near the Iraqi border.

They were the latest casualties in Syria’s devastating civil war as it entered its ninth year with 370,000 dead.

All that remains of a once-sprawling proto-state that the ISIS extremists declared in 2014 is a battered riverside camp in Baghouz.

The SDF and coalition warplanes have rained fire on the enclave since last Sunday, blitzing more than 4,000 ISIS fighters and family members into surrender.

Their on-off assault has been mostly fought at night, suspending major operations dayside to allow more surrenders, especially of civilians.

In total, over 61,000 people have streamed out of ISIS-held territory since December, according to the Syrian Observatory for Human Rights.