BEIRUT -- Residents in the Syrian capital awoke to two loud explosions Sunday amid reports from activists that the Damascus headquarters of the ruling Baath party had been hit by several rocket-propelled grenades.
There was no immediate confirmation of the report but the Free Syrian Army, a group of military defectors, claimed responsibility for the attack.
In a statement posted on the group's Facebook page, the FSA said the assault caused casualties and damage to the building. But eyewitnesses said the party headquarters appeared intact and reported no significant security deployment around it.
If true, the Damascus attack on the Baath Party's main building would signal a significant shift in the eight-month revolution against President Bashar Assad, bringing the violence that has engulfed much of the rest of the country to the heart of the Syrian capital, which has so far been relatively untouched.
In Cairo, the Arab League said it has rejected amendments proposed by Syria to a peace plan to end the crisis, saying the changes put forward by Damascus alter the plan's "essence."
The 22-member organization did not give details of Syria's proposed amendments. But it said in a statement Sunday that Damascus' proposals were unacceptable because they introduce "drastic changes" to the mandate of an observers' mission the league wants to dispatch to Syria to ensure the implementation of the peace plan.
The Arab League has already suspended Syria's membership over its failure to abide by the plan, which calls for the withdrawal of the government's tanks from the streets, the release of political prisoners and a halt to attacks on civilians.
An Arab League official speaking on condition of anonymity because he was not authorized to brief the media said the Syrian government was required to implement the peace plan in its entirety.
Assad, meanwhile, vowed to continue with a security crackdown to crush "militants" who he says are massacring Syrians on a daily basis.
"The role of the government is to fight those militants in order to restore stability and to protect civilians," he said in an interview with Britain's Sunday Times newspaper. He also repeated earlier warnings that any foreign military intervention in Syria would "shake the entire Middle East."
On Sunday, activist groups said at least three people were killed in continuing operations by security forces, including two in the flashpoint central city of Homs and one in northern Syria.
Syria's uprising against Assad, although largely peaceful, has grown more violent and militarized in recent weeks, as frustrated protesters see the limits of peaceful action. Army dissidents who sided with the protests have also grown bolder, fighting back against regime forces and even attacking military bases, raising fears of a civil war in Syria.
The Free Syrian Army group of dissident soldiers this week staged their boldest operation yet, striking a military intelligence building in a Damascus suburb.
If Sunday's attack on the Baath Party headquarters in Damascus is confirmed, it would mark the first assault on a government building in what has so far been a relatively quiet central Damascus.
The Local Coordination Committees activist network and several residents reported several explosions in the district of Mazraa in the heart of the Syrian capital.
The LCC said in a statement that the building had been hit at daybreak Sunday by several rocket-propelled grenades and that two fire brigades headed toward the area amid a heavy security presence. The group said it had no further details.
The British-based Syrian Observatory for Human Rights said unknown gunmen on motorcycles threw first a sound bomb and then fired RPGs at the Baath party headquarters, hitting the external wall of the building. Two other grenades missed the target, it said.
Residents in the Syrian capital said they heard two loud explosions but could not confirm whether the building had been hit.
"I woke up to the sound of two loud thuds," said a resident of the area who asked that he remain anonymous for fear of reprisals. "We have no idea what they were."
The U.N. says more than 3,500 people in Syria have been killed in the crackdown since the start of the uprising in mid-March. Assad, in the interview, said more than 800 Syrian officers and security forces were killed.
"We are not talking about peaceful demonstrations, we are talking about militants," he said.
Syrian TV said the country's foreign minister will announce Damascus' position on the Arab initiative later Sunday.
Assad, however, lashed out at the Arab League and said the peace plan was aimed at giving the international community an excuse to meddle in his country.
"It's been done to show that there's a problem between the Arabs, thus providing Western countries with a pretext to conduct a military intervention against Syria," he said.
The consequence of any such intervention, he warned, would be "an earthquake that would shake the entire Middle East."
In the interview, Assad said he feels "pain and sorrow" for the bloodshed but added the solution was to eliminate the militants he blames for much of the violence. The Assad regime maintains the militants are playing out a foreign agenda to isolate and weaken Syria.
"The conflict will continue and the pressure to subjugate Syria will also continue," he said. "However I assure you that Syria will not bow down and that it will continue to resist the pressure being imposed on it."
Assad, who took over power from his late father, Hafez, in 2000, said there would be parliamentary elections in February or March, after which there would be a new government and new constitution.
"That constitution will set the basis of how to elect a president ... the ballot box should decide who should be president."