At least 13 people were killed and many others wounded when a car bomb went off in a suburb of Syrian capital Damascus, a monitor group reported on Wednesday.The explosives-laden vehicle exploded overnight near a mosque in al-Tal suburb, said the Syrian Observatory for Human Rights.The Britain-based watchdog group said the death toll was likely to rise in view of the number of critically wounded people.No party has so far claimed responsibility for the attack, and its circumstances remained murky on Wednesday.Al-Tal was one of the suburbs that sided with rebellions against the rule of President Bashar al-Assad at the beginning of the Syrian crisis.The town, which is tucked in the mountains of northern Damascus, harboured fighters of Free Syrian Army, a loosely organised rebel movement that was overshadowed by the presence of the extremist group.Syrian forces were quick to quell the rebellions in the area after battles there and finally the warring sides established a truce in al-Tal.