Syrian regime air strikes and shelling killed 17 civilians, including seven children on Friday in the Palestinian camp of Yarmouk in southern Damascus, a Britain-based monitor said.

Regime forces have pounded southern districts of the capital since April 19, to try to expel the Daesh group from the area, after the terrorists refused to leave under an evacuation deal.

That bombardment intensified on Friday, the Syrian Observatory for Human Rights monitor said, as regime forces advanced against Daesh inside the districts.

"Army units backed by the air force and artillery have advanced on numerous axes" in southern Damascus, including the district of Hajar al Aswad, "after breaking through terrorist defences," regime news agency SANA said.

The advance "inflicted great human and material losses" on the militants, it said.

Syrian regime television said the army has seized control of buildings and a "network of trenches and tunnels" from Daesh in Hajar al Aswad.

In the adjacent neighbourhood of Qadam, two children were killed in "mortar rounds fired by terrorist groups," it said.

The Observatory said pro-government forces took control of "buildings and streets in Hajar al Aswad and Qadam after attacking the districts at dawn."

Regime forces were locked in violent clashes with Daesh fighters on Friday morning, the monitor said.

Heavy air strikes and shelling had targeted Yarmouk and the edges of Hajar al Aswad and Qadam since the early morning.

Daesh has held parts of Hajar al Aswad and Yarmouk since 2015 and seized Qadam last month.

Dozens dead

At least 74 regime personnel and 59 Daesh fighters have been killed in eight days of fighting in southern Damascus, the monitor said.

The latest civilian deaths bring to 36 the number of non-fighters killed in regime bombardment in that same period, it said.

Yarmouk and its surroundings are now Daesh's largest urban redoubt in Syria or neighbouring Iraq.

The extremists have lost much of the territory they once controlled in both countries since they declared a cross-border caliphate there in 2014.

Yarmouk was once home to around 160,000 people, but today just a few hundred people remain, the UN agency for Palestinian refugees has said.

Bashar al Assad's regime set its sights on the south of the capital after reconquering a major opposition bastion east of Damascus earlier this month.

Eastern Ghouta fell after a blistering air and ground assault and Russia-backed evacuation deals that saw tens of thousands of people bussed out to northern Syria.

More than 350,000 people have been killed and millions displaced since Syria's war started in 2011 with the brutal repression of anti-regime protests.