Fierce fighting has escalated between the Free Syrian Army and government troops in the suburb of Damascus, the capital, a day after 60 people were killed across the country, according to reports.
Meanwhile, European and Arab nations have pressed for UN Security Council backing for an Arab League plan calling on Bashar al-Assad, Syria's president, to stand down, but Russia said their proposed resolution crossed its "red lines".
Move comes amid reports of army tanks shelling Homs' Baba Amr neighbourhood on Saturday, and growing calls within the Syrian opposition for an all-out armed resistance, sources tell Al Jazeera.
Morocco presented a draft resolution to the 15-nation Security Council, drawn up by Britain, France and Germany with Arab states, that seeks to end months of UN deadlock over Syria.
Days of tough talks loom before any vote is held. No action is likely before Arab League Secretary-General Nabil Elaraby and Qatar's Prime Minister Sheikh Hamad Bin Jassim Al Thani brief the council on Tuesday.
Backers of the new resolution hope opponents will be swayed by the Arab League's involvement and by a new upsurge in violence in Syria in efforts to end the deadly crackdown on dissent which the UN says has left more than 5,400 dead.
General Mohammed Ahmed Mustafa al-Dabi, the head of an Arab League monitoring mission deployed to Syria, said unrest had soared in the last week "in a significant way", especially in the flashpoint central cities of Homs and Hama and in the northern Idlib region.
The draft resolution supports an Arab League plan released last weekend demanding that Assad hand over powers to a deputy so that new elections can be held.
The text demands an immediate end to the government violence and "encourages" all states to follow sanctions imposed by the Arab League against Syria in November, but contains no mandatory action.
Syria's UN representative Bashar Jaafari remained defiant, saying: "They are talking about my country without consulting us, without sharing with us their concerns, their remarks".
"They deal with us as if we are a former colony, that we should subjugate ourselves to their will. They are wrong and they will be disappointed."
Russia and China vetoed a previous European resolution in October, accusing the West of seeking "regime change".
Vitaly Churkin, Russia's UN ambassador, said the Europe-Arab draft resolution was unacceptable in parts, but his country was ready to "engage" on it.
Churkin was critical of the Arab League, accusing it of seeking to "impose" a solution on Assad before talks had started between the government and opposition groups.
"Syria will not be Libya," he declared.
"The Arab League may have its ideas where political dialogue should go. Certainly they are free to express those ideas but the Security Council should not be a tool to impose specific solutions on countries including in this particular case Syria," he said.
Despite the opposition, many European envoys said an agreement with Russia and its allies was possible.
"I think we have the chance today to open a new chapter on Syria," Germany's UN ambassador Peter Wittig said.
Activists said 60 people were killed on Friday, as anti-Assad protests were held in many locations across the country.
A pro-government rally was also held in Damascus, with protesters carrying pictures of the president and banners denouncing the Arab League.
Demonstrators opposed to Assad gathered under the slogan "We have the right do defend ourselves", as an increasing number of civilians and army defectors have taken up arms against the state.
In-depth coverage of escalating violence across Syria
"It is our right to take up arms and we are not going to shy away from this any longer," an activist from Homs now living in Turkey told Al Jazeera.
"We are being killed. We waited for any action from the Arab League and the United Nations and none was forthcoming."
The state-run news agency SANA said a 10-year old boy had been killed and several others injured in "an explosive device blast and shooting by an armed terrorist group" in the Damascus neighbourhood of al-Midan.
SANA also said a "law enforcement member", a woman and a child were killed in two separate shooting incidents in Homs.
Much of Friday's violence occurred in Homs, where activists reported heavy fighting for a second day. Mohammad Saleh, a centrist opposition figure and resident of the city, said there had been a spate of sectarian kidnappings and killings on Thursday between the city's population of Sunnis and Alawites, the Shia offshot which the Assads belong to.
There was also a string of attacks by gunmen on army checkpoints, Saleh said. Checkpoints are a frequent target of dissident troops who have joined the opposition.
The Security Council has been split on Syria since last year's NATO's airstrikes in Libya. Russia, China, and other council members including South Africa and India accuse NATO of abusing UN resolutions on Libya to deliberately bring down Muammar Gaddafi.
China's diplomats did not comment after the talks, but diplomats said its ambassador, Li Baodong, had insisted in the closed council meeting that there must be no repeat of the Libya resolutions of last year.
Baso Sangqu, South Africa's UN ambassador, said there was a "tint" of regime change in the new Europe-Asia proposition.
"Obviously if there is anything that could explicitly have regime change in it then it will cause problems for some of us," Sangqu told reporters.
Mark Lyall Grant, Britain's UN envoy, dismissed any suggestion that there were sanctions or an arms embargo in the text.
"We want, as do the Arabs, a unanimous resolution," he said. "Frankly the time has come when we should be supporting the Arab League."