BEIRUT • The Islamic State in Iraq and Syria (ISIS) yesterday overran a government-controlled hospital in eastern Syria, killing 20 pro-government soldiers and taking medical staff hostage, a monitor said.

The Syrian Observatory for Human Rights said the militants attacked Al-Assad hospital in Deir Ezzor as they pressed an advance to try to control the oil-rich city and its vital airbase.

The attack sparked clashes with government forces providing security for the hospital in which six militants were also killed, the monitor said.

"IS attacked Al-Assad hospital at the city's western entrance, killing at least 20 soldiers," said observatory head Rami Abdel Rahman, using another acronym for ISIS.

The militants "seized the hospital and captured the medical staff, holding them hostage", he said.

ISIS controls about 60 per cent of Deir Ezzor, including the centre and the north of the city.

It has imposed a siege on government-held districts in the south and east where about 200,000 civilians have been trapped since March 2014.

The militants, who also control nearly all the surrounding province, have repeatedly attacked the government enclave and seized several neighbourhoods since the start of this year.

But their efforts to capture the airbase located in the south of the city have been crushed by elite government troops.

In the northern city of Aleppo, the observatory said, seven civilians including two children were killed over the previous 48 hours in rebel shelling of government- held western sectors.

A ceasefire in the divided city expired on Wednesday.

The observatory also reported heavy fighting on the edge of rebel-held Daraya, a town near Damascus under siege by government forces since 2012.

AGENCE FRANCE-PRESSE