There has been renewed fighting in Syria ahead of a UN General Assembly vote condemning its own Security Council for failing to end the unrest.
The army has been shelling rebel positions in the largest city, Aleppo. There was also bloodshed in Hama and the capital, Damascus.
The aim of the UN resolution is to pressure the Security Council to act.
It follows the resignation of UN-Arab League envoy Kofi Annan and the failure of his six-point peace plan.
Correspondents say this is a clear recognition that the political process has failed.
Activists say more than 20,000 people – mostly unarmed civilians – have died in 17 months of unrest.
‘Build-up’
In an unconfirmed report, Reuters news agency quoted witnesses as saying “dozens” of army vehicles had entered the Tadamon district of Damascus, the rebels’ last stronghold in the capital.
Fighting has continued in Tadamon for two days and at least 15 people were reported killed when mortars hit the nearby Palestinian refugee camp at Yarmouk late on Thursday.
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[Victory in Aleppo] is going to open the whole northern part of Syria”
Thoebah Knafane FSA fighter
Hamas, the Palestinian group in power in the Gaza Strip, described the attack as a heinous crime – the Syrian government and rebels blamed one another.
Fighting is continuing in Aleppo, where government forces have been trying to reclaim areas seized by the Free Syrian Army (FSA) in the past two weeks.
On Friday, the FSA said it had taken 50% of the city of more than two million people. The claim could not be independently verified.
UN peacekeeping chief Herve Ladsous told the Security Council that UN observers in Aleppo were seeing “a considerable build-up of military means, where we have reason to believe that the main battle is about to start”.
One FSA fighter, Thoebah Knafane, told BBC News that winning Aleppo would “open the whole northern part of Syria” for the opposition.
Fighters, she said, were being trained in both Syria and Turkey and she personally had been instructed in using an M16 assault rifle and a pistol.
Activists say 170 people died across the country on Thursday – including dozens in Hama, to the south of Aleppo.
The FSA has issued a statement denying responsibility for the public killing of alleged government loyalists in Aleppo on Tuesday and condemning the shootings, video of which was posted online.
Russia’s defence ministry has denied that a group of naval landing ships it is sending to the Mediterranean on exercises plans to call at its base in the Syrian port of Tartus.
It said the ships would have their own supply ships, but added that the navy had every right to stop at Tartus for supplies if it wanted to.
Text ‘toned down’
Russia and China have blocked attempts in the UN Security Council to impose sanctions against Damascus.
The proposed General Assembly resolution, which would not be legally binding, requires only a simple majority of the 193-member General Assembly to pass.
Drafted by Saudi Arabia, which openly supports the armed rebellion against President Bashar al-Assad’s rule, the text condemns the Syrian government’s use of “heavy weapons” and its failure to withdraw forces from civilian areas, as demanded by Mr Annan’s peace initiative.
Russia and China have vetoed resolutions on the crisis three times, citing opposition to any action which might be seen as regime change imposed from outside.
Iran has accused unspecified “interfering countries” of causing the failure of Kofi Annan’s mission.
In another development, Alistair Burt, UK Foreign Office minister for the Middle East, confirmed to the BBC that the UK would be providing further communications equipment to the opposition in Syria in the next month.
US media say US President Barack Obama has signed a covert order authorising support for Syrian rebels.