AMMAN (Reuters) - An explosives-laden car blew up on Monday in a heavily policed district in the center of the Syrian capital Damascus, causing injuries and extensive damage, state media said.

The explosion in the Kafr Sousa neighborhood close to the main Umayyad Square that connects the city center with several highways hit an area where some of Syria's main security installations are based.

The U.K.-based Syrian Observatory for Human Rights which tracks violence across the country said the blast was near an Iranian school and that there were dead among the casualties.

Insurgents fighting to topple President Bashar al Assad say the district houses many recruits from Iranian-backed militias fighting alongside Assad's army. A rebel group claimed it had targeted Iranian-backed militias in the area.

State media showed pictures of smashed glass and metal strewn from the front of a residential building where the car bomb was detonated.

Car bombings in the city center are relatively rare.

On Sunday mortars hit a restaurant in the capital's old quarter, killing at least six people and injuring scores, according to a witness and state media.

(Reporting by Suleiman Al-Khalidi; Editing by James Dalgleish)