Air raids in Syria's Idlib province carried out by the regime killed at least 11 people overnight, mostly civilians, as regime forces made advances in Aleppo province, AFP reported Monday (February 27th).

The regime carried out airstrikes after midnight on several areas in the town of Ariha, said Syrian Observatory for Human Rights head Rami Abdel Rahman.

"The preliminary toll is 11 killed, including at least seven civilians," three of them children, he said.

Others were still missing, and rescue teams were searching for anyone trapped under the rubble, Abdel Rahman added.

Leith Fares, a rescue worker in Ariha, said his team had pulled at least 20 wounded people out of the rubble.

"We have been working since 3 a.m. to rescue victims still under the rubble of two four-story buildings that totally collapsed on the residents inside," he said.

"We are still looking for two families, estimated at eight to 10 members each, that are still trapped," Fares said.

The deaths come two days after 10 civilians were killed in regime airstrikes on Ariha, held since 2015 by an anti-regime coalition dominated by extremists.

Idlib province has been battered by heavy airstrikes in recent weeks, with intensifying bombing raids by regime warplanes in particular, the Observatory said. It also has been rocked by infighting between opposition and extremist factions, including al-Nusra Front.

A Syrian military source said Monday that the army had "seized 18 towns and villages, including the town of Taduf and a number of strategic hilltops in eastern Aleppo province, totalling about 600 square kilometres".

Taduf had been held by the "Islamic State of Iraq and the Levant" (ISIL) and lies near al-Bab, a key town where opposition fighters backed by Turkish forces defeated ISIL last week.

ISIL on Monday withdrew from nearly two dozen villages near Manbij, in what the Observatory called a sign of "swift collapse" of extremist ranks.

Manbij is held by the Syrian Democratic Forces (SDF), an Arab-Kurd opposition alliance.