DAMASCUS: Syrian rebels launched a devastating car bomb attack Monday that killed 50 pro-regime fighters, a watchdog said, as air strikes pounded rebel positions and the opposition met for talks on an overhaul.

The suicide car bomb attack on a military post in the central province of Hama struck early Monday, killing at least 50 government troops and loyalist militiamen, the Syrian Observatory for Human Rights said.

“The post, located at the Centre for Rural Development, is the largest gathering place for troops and pro-regime militiamen in the region,” said the Observatory, a Britain-based monitoring group.

Regime aircraft meanwhile continued to pound rebel-held positions around the country, with one air strike killing at least 20 rebel fighters in the town of Harem in the northwestern province of Idlib, the Observatory said.

The rebels have scored significant wins in recent weeks and hold swathes of territory in the country's north, but have come under intense bombardment from the air as President Bashar al-Assad's regime seeks to reverse rebel gains.

Clashes also broke out Monday around Damascus and in Syria's second city Aleppo, and state television reported a bomb attack in the residential Mazzeh district of the Syrian capital killed 11 people and wounded dozens.

“Terrorists carried out an explosion in the Jabal area of Mazzeh district, which was crowded with people,” state television said. After giving an initial number of four dead, the channel later raised the toll to 11 and said children were among the victims.

The Syrian Observatory for Human Rights also said 11 people had died when the booby-trapped car exploded in Mazzeh, an upscale neighbourhood of west Damascus that houses embassies and a number of security headquarters.

The Britain-based Observatory, which relies on a network of activists and medics on the ground, said about 30 people were wounded, including eight who were in critical condition.

Fighting erupted in southern districts of the capital on the edge of the Yarmuk Palestinian camp, the Observatory said, with Palestinian sources saying 31 people had died from shelling at the camp on Sunday and Monday.

In Aleppo, fighting broke out at a roundabout at the northwestern entrance to the city in Zahraa district and on the airport road to the southeast, the Observatory and residents said.

One resident of a district near Zahraa said Monday's fighting in the area was the heaviest in recent days.

“It's been almost one week that we are living in terror at night. We hear everything, gun battles, tank shelling, explosions... The clashes before dawn today were the worst all week,” Samir, a 37-year-old pharmacist, told AFP.

The Observatory said at least 105 people, including 55 soldiers and pro-regime fighters, had been killed in the violence on Monday.

The escalating conflict has added urgency to a meeting of the Syrian National Council in Qatar, where the United States is reportedly pressing for a new umbrella organisation to unite the country's fractured opposition.

According to the reports, which emerged after US Secretary of State Hillary Clinton said the SNC was not representative, long-time dissident Riad Seif is touted as the potential head of a new government-in-exile dubbed the Syrian National Initiative.

Seif on Sunday denied planning to head such a government, while SNC chief Abdel Basset Sayda denounced what he called “efforts to bypass the SNC”.

At the talks on Monday, SNC members approved a restructuring project that will see the organisation add 200 new members representing 13 different political groups, SNC spokesman Ahmad Kamel told AFP.

On Tuesday SNC members will hold a debate on a proposal put forward by Seif to create a new political body to represent the opposition, folding in the SNC and other anti-regime groups.

The SNC lashed out on Friday at alleged US interference with the opposition, accusing Washington of undermining the revolt and “sowing the seeds of division” by seeking its overhaul.

On the diplomatic front, Russian Foreign Minister Sergei Lavrov accused countries that support Syria's rebels of encouraging them to fight rather than pressuring them to negotiate an end to the conflict.

Russia, one of the Syrian regime's most influential foreign allies, held no sway over the rebels, Lavrov said at a news conference in Cairo with his Egyptian counterpart Mohammed Kamel Amr.

Countries that do have influence over the rebels, among them some Gulf Arab states and Western powers such as the United States, should encourage them to “sit at the negotiating table,” Lavrov said.

Instead, some of these countries prefer to “unify the rebels not on the basis of negotiations but on the basis of continuing the fighting,” he said.

Lavrov met Sunday with Arab League chief Nabil al-Arabi for talks, after which Arabi said “there wasn't any agreement on anything” during the discussions.

Russia and China have stymied Western- and Arab-backed efforts to put more pressure on Assad's regime by blocking UN Security Council resolutions.

The Observatory says more than 36,000 people have died since the uprising against Assad's rule broke out in March 2011, first as a protest movement inspired by the Arab Spring and then as an armed rebellion.