Syrian forces tightened their grip on Damascus' outskirts on Monday, as the Arab League pushed a UN resolution drawn up with Western powers condemning President Bashar al-Assad's regime.
The violence has been described by activists as the most intense since the beginning of the 10-month uprising, with 80 people killed across Syria on Sunday alone, half of them civilians, the Syrian Observatory for Human Rights said.
Regime forces seem intent on wresting back complete control of Damascus suburbs that have intermittently fallen into the hands of rebel fighters in recent weeks.
Across the area, the government soldiers have set up checkpoints at strategic intersections in search of armed fighters or suspects wanted by security services.
The rebel Free Syrian Army said 50 more officers and soldiers turned their back on Assad on Saturday and in a "steady progression of fighting towards the capital" clashed with army regulars only eight kilometres (five miles) from Damascus.
The regime, in turn, has launched "an unprecedented offensive" using heavy artillery against villages in Damascus and Hama province of central Syria, the rebel army said.
It reported clashes on Sunday as close as four kilometres to the capital.
"The more the regime uses the army, the more soldiers defect," Ahmed al-Khatib, a local rebel council member on the Syrian capital's outskirts, told AFP.
Armed clashes on Monday killed six members of Syria's security forces and three civilians at Hirak, in southern Daraa province, the Observatory said.
"Dissident soldiers on Monday attacked a minibus carrying six security officers on their way to make arrests in Hirak, killing all of the passengers," the group said.
Two tanks then entered the town and opened fire, killing three civilians, the group said.
The latest spike in violence, on top of what the United Nations said at the start of January already added up to 5,400 killings, pushed the Arab League to suspend its mission to Syria in a surprise move on Saturday.
League chief Nabil al-Arabi, who is expected in New York Monday, said the decision was taken after Damascus "chose the option of escalation".
The 165 observers deployed a month ago after Damascus agreed to an Arab League plan foreseeing a halt to the violence, prisoners freed, tanks withdrawn from built-up areas and free movement of observers and foreign media.
Arabi said on Sunday he hopes Moscow and Beijing will allow the UN Security Council to issue a resolution backing a new League plan to end the crisis.
"I hope these two countries will alter their position concerning the draft UN Security Council resolution which would adopt the Arab plan," he said, according to Egypt's official MENA news agency.
This plan looks to a halt in the violence and Assad transferring power to his deputy ahead of negotiations -- a formula flatly rejected by Damascus.
Moscow opposes the draft UN resolution, and it has proposed its own draft assigning equal blame for the violence on both Assad and the opposition, an option dismissed by the West.
Russia has close trade ties with its Soviet-era ally, signing a new warplane delivery contract with Damascus this month, and it leases a Syrian port on the Mediterranean for its navy.
UN chief Ban Ki-moon said Sunday that Assad must end the killings.
"First and foremost, he must stop immediately the bloodshed," Ban told reporters. "The Syrian leadership should take a decisive action at this time to stop this violence. All the violence must stop."