BEIRUT/WASHINGTON: Sporadic clashes between Daesh (ISIS) militants and U.S.-backed fighters erupted Friday in the Daesh-held city of Manbij after the extremists ignored a 48-hour offer from the day before to leave the besieged town without a fight, opposition activists and a Kurdish official said.

Also Friday, regime troops seized the town of Huraira in the Wadi Baraka area, in rural Damascus, after heavy clashes with Al-Qaeda-linked Nusra Front and Ahrar al-Sham fighters, said the Media War Center, a news outlet close to the regime.

In another area of the Damascus countryside, three people were killed and scores were wounded in airstrikes on the city of Douma in Eastern Ghouta, with numbers of casualties expectex to increase due to large number of wounded, the Britain-based Syrian Observatory for Human Rights said.

In Manbij, meanwhile, fighting is forcing many civilians to flee, and the Observatory said about 200 civilians fled the town in the morning hours.

A Facebook page that covers Manbij posted two photographs of a few dozen people, mostly women and children, saying they “risked their lives” to flee the town’s southern neighborhood of Hazawneh. The predominantly Kurdish U.S.-backed Syria Democratic Forces have been on the offensive in Manbij for weeks, backed by U.S.-led coalition raids.

Sherfan Darwish of the SDF said the extremists did not respond to the offer and clashes erupted anew Friday. The Daesh-linked Aamaq news agency said the U.S.-led coalition carried about 20 raids on the center of Manbij.

Col. Chris Garver, a U.S. coalition spokesman, said Daesh is using civilians as human shields in Syria at a time when the coalition has been accused of killing dozens of civilians in strikes near the town.

The Observatory accused the coalition of killing 56 civilians, including 11 children, as they fled Tuesday from a village near Manbij.

Daesh “used civilians as human shields and as bait” to draw the fire of the SDF toward the civilians, Garver said by video conference from Baghdad.

In other developments, 38 Syrian troops and pro-regime fighters were killed when rebels blew up a tunnel under a government position in Aleppo city, the Observatory said. The blast brought down a building used by the regime.

A video posted online by the Thuwwar al-Sham rebel group purported to show the incident, with members of the force walking through a long tunnel and preparing barrels full of explosives.

“We are now inside the tunnel that will be detonated soon, God willing, the tunnel under the traffic branch building, which is an important headquarters for the Assad regime and its mercenaries,” a rebel says in the video.

In Geneva, spokesman Jens Laerke of the U.N. Office for the Coordination of Humanitarian Affairs said a convoy carrying assistance for 32,000 people arrived Friday in the hard-to-reach town of Halat al-Madeh in the central province of Hama.