A Syrian dissident was killed by security forces before his body was thrown off the rooftop of his home in front of his wife and children, the Syrian Observatory for Human Rights said Thursday.

The Britain-based monitoring group said the incident took place on Wednesday in the town of Al-Maadamiyeh, located on the outskirts of Damascus.

"Security forces launched a raid on the home of militant Nasser Mohammed Said Sghayer, 30," it said in a statement. "Fearing arrest, he sought refuge on the roof of his house and security forces threatened to arrest his two children if he did not surrender."

It added that when he failed to heed their call, troops rushed to the roof and opened fire, killing him on the spot.

"They then threw his body from the roof in front of his wife and children,"

the Observatory said.

It said Sghayer had served four months in prison and had been released last week. His father has been behind bars for seven months.

The Observatory called for an independent inquiry into his death.

The killing came amid an unprecedented 10-month revolt in Syria that has left more than 6,000 people dead, according to rights groups. (AFP)