Two rocket-propelled grenades hit a building belonging to the ruling Baath party in the heart of Damascus yesterday morning, activists claimed.
The attack, the first reported inside the Syrian capital, came as the Arab League rejected demands made by President Bashar al-Assad's regime to amend a plan meant to halt the brutal security crackdown that has left at least 3,500 people dead.
A witness told Reuters news agency: "Security police blocked off the square where the Baath's Damascus branch is located. But I saw smoke rising from the building and fire trucks around it. It seems to have been intended as a message to the regime."
While calling the reports "baseless" at a press conference yesterday, the Syrian Foreign Minister, Walid al-Moallem, did seem to acknowledge some kind of attack.
Coming shortly after an assault on the air force intelligence headquarters just outside the capital, the reported attack contributes to a growing sense that the Syrian opposition is ready to make a more co-ordinated use of force against the Assad regime. The Free Syrian Army, whose leader, Colonel Riad al-Asaad, is based in neighbouring Turkey, claimed responsibility for the attack.
Despite increased pressure, President Assad has vowed to continue a crackdown on what he claims are armed gangs. In an interview with The Sunday Times newspaper, Mr Assad said he planned to hold elections next year and was prepared to fight and die if faced with a foreign intervention.
Meanwhile, the Arab League rejected Syrian government amendments to its plan to end the crisis, saying they were unacceptable because they introduced "drastic changes" to the mandate of proposed foreign observers. Many analysts believe the conflict has reached a crucial point. But opposition activists outside the country warned that the fractured movement had to unite if it were to succeed.
The opposition Syrian National Council had to reorganise itself, said Omar al-Muqdad, a senior activist who is now based in Turkey. "It's not unified. They need to fix the council. Finally, [the conflict in Syria] is a political subject."
Even one of the growing number of army defectors voiced frustration with how the opposition campaign was being carried out. Basim al-Khaled, a lieutenant who defected last May, cast doubt on the Free Syrian Army's ability to carry out attacks inside the country. "Colonel al-Asaad has no control on the ground," he said. "Because [he] is out of Syria, he controls nothing inside the country."