Al-Qaeda terrorists are believed to have attacked two government buildings in the Syrian capital of Damascus, said Sana, the official news agency.

The attacks targeted the State Security Directorate and another security branch in the city.

"Preliminary investigations indicated that that the criminal attack carries the blueprints of al-Qaeda," Sana said.

Two al-Qaeda suicide bombers detonated vehicles full of explosives, according to the report.

The number of injuries is not known.

Opposition activists accused the government of staging the attack, which took place just a day after the Arab League monitoring team arrived.

The group is part of an initiative aimed at ending violence in a country where the UN says more than 5,000 people died in a brutal crackdown on protesters.

President Bashar al-Assad has denied claims the security forces were behind the deaths. He blames terrorists and armed groups, which he says are backed by "foreign powers".