At least 14 people have been injured when a suicide car bomb exploded in a Damascus suburb and damaged one of Shiite Islam's holiest shrines, Belfast Telegraph said.

The golden-domed Sayyida Zainab shrine attracts tens of thousands of Shiite pilgrims from around the world every year who come to visit the tomb, which is believed to house the remains of the granddaughter of the Prophet Mohammed. The site is popular with Iranian and other Shiite pilgrims and tourists.

Witnesses said the bomber detonated his van in a car park about 50 metres from the shrine. Guards tried to stop him from getting into the area but he pushed through. The blast shattered the shrine's windows and knocked down chandeliers and electric ceiling fans and caused cracks in some of its mosaic walls.

Six tourist buses and more than 30 cars and a small police bus also were damaged. It was not immediately clear whether the shrine was the intended target. The site of the blast is only 15 metres from a police station.

Car bombs and suicide bombings have become common in Syria as the 15-month uprising against President Bashar Assad becomes increasingly militarised.

Western officials say there is little doubt that Islamist extremists, some associated with the al Qaida terror network, have made inroads in Syria as instability has spread.

On June 14 rebels reportedly clashed with government forces in several parts of the country and troops continued to pound rebel-controlled areas in the central province of Homs.

The Britain-based Syrian Observatory for Human Rights said three civilians were killed overnight in clashes in Homs city. Another died in the rebel-held town of Rastan north of Homs, which has been under constant fire from regime forces for days.