A Syrian army defector said that the rebels controlled 60 per cent of the country and that all they needed was limited military intervention from NATO to help them topple President Bashar Assad, a pan-Arab daily newspaper reported on Monday.

"All we need from NATO are two air attacks on the presidential palace to topple the regime and we will be able to control all the Syrian cities," Major General Adnan Salo, who is a former head of the chemical weapons unit in the Syrian army, told Asharq al-Awsat.

Meanwhile, Syrian rebels on Monday fought fierce battles with government forces in Damascus, including in an area close to President Bashar Assad's residence, activists said.

Videos posted on opposition websites showed fighting allegedly taking place in Kfar Soussa, an area in the capital close to the presidential palace.

The Syrian army sent reinforcements after the clashes and checkpoints were erected across the capital, activists said.

The Syrian Observatory for Human Rights said the clashes that started on Sunday and lasted until the early hours of Monday were the fiercest in Damascus since the start of the uprising against Assad 16 months ago.

The fighting occurred ahead of a visit to Russia by international envoy Kofi Annan, who will urge Syria's strongest ally to put more pressure on Assad to stop the violence.

Syria allies Russia and China oppose Western and Arab efforts to pass a UN Security Council resolution that threatens sanctions against Assad if he fails to stop the violence and start a political transition.

Damascus residents said the sound of explosions and heavy machine gunfire were heard in the city on Monday.

"Most of us spent the night sleeping in corridors," said a Damascus resident who gave her name as Zeina. "It was a scary night.."

Anti-regime protesters managed to briefly block a road leading to Damascus airport at dawn, activists said.

Activists said government forces also shelled rebel-controlled areas in the central province of Homs.

Russian Foreign Minister Sergei Lavrov said on Monday that Western powers were unwilling to compromise on a solution to the Syrian conflict and accused them of being insincere in their quest for an end to the bloodshed.

"Our Western partners were either insincere or not ready to negotiate in Geneva," Lavrov told journalists, referring to a June 30 international conference on Syria.

He rejected criticism that Russia and China were responsible for the continued violence because they had refused to back Western sanctions against the Syrian regime. He said Moscow supported neither the Syrian government nor the rebel.

Also Monday, Morocco ordered the Syrian ambassador to leave the North African kingdom and called for a transition to democracy in Syria, and Damascus retaliated by declaring the Moroccan ambassador there persona non grata.

Morocco's Foreign Ministry did not immediately explain the timing or the reason for its decision to expel Ismail, but said in a statement the situation in Syria "cannot remain as it is."

Earlier on Monday rumors circulated that the ambassador to Rabat, Nabih Ismail, had also defected to the rebel side. A Syrian embassy official denied this but had no further comment.