Forces loyal to Syrian President Bashar al-Assad killed at least 25 people Monday as they battled their way deep into eastern suburbs of Damascus to seize them back from rebels, activists said from the edge of the sprawling capital.

The death toll comprised 19 civilians, mostly killed in tank and mortar bombardment, and six members of the Syrian Free Army, the activists added. Their account could not be confirmed. Syria restricts access by most foreign journalists.

The Free Syrian Army is a loosely grouped organization of army defectors who have turned against Assad and joined a mass protest movement against his 11 year rule.

Fighting subsided by night as core units of Assad's military extended their control of urban concentrations bordering old farmland, known as the Ghouta, and members of the Syrian Free Army pulled back, the activists said.

The Free Syrian army moved away to the edges of the suburbs. Assad's brigades are making arrests and looting houses, Kamal, one of the activists, said by phone.

He added that at least 200 people were arrested in the suburb of Hammouriya, one of three suburbs that have been a focus of the military offensive, which began Saturday.

The Syrian government says it is sweeping Ghouta for terrorists. It says it is fighting an uprising led by foreign-backed militants, who have killed thousands of members of the security forces.

(Reporting by Khaled Yacoub Oweis, Amman newsroom; Editing by Peter Graff)