Activists say Syrian forces have shelled two central districts in the city of Homs, even as a hard-won UN-backed
ceasefire entered its third day.
The overnight bombardment of the city's Jurat al-Shayah and al-Qarabis neighbourhoods continued into the morning, wounding several people, the British-based Syrian Observatory for Human Rights said on Saturday.
"I have heard eight shells fall in the past hour," Karm Abu Rabea, a resident activist who lives in an adjacent neighbourhood, told the Reuters news agency.
The UN Security Council is expected to vote later on Saturday on a revised Western-drafted resolution allowing a ceasefire observer mission in Syria even though Russia's support remained in doubt.
The United States called for the vote after a second day of wrangling with Russia over security guarantees for the first 30 unarmed military monitors that Kofi Annan, the UN-Arab League peace envoy, wants in Syria early next week.
The United States called for the vote at 15:00 GMT on Saturday, but Vitaly Churkin, Russia's ambassador to the UN, said he was not "completely satisfied", describing negotiations as "rather difficult".
Russia and China have twice used their veto rights as permanent members to block a tougher stance by the council against the Syrian government, but both countries have expressed support for a peace plan devised by Annan.
The two countries had earlier submitted alternative draft resolutions for the vote by the 15-member body on the proposed deployment of 30 observers to Syria to monitor a ceasefire implemented as part of a UN-Arab League peace plan.
The United States-proposed resolution, backed by Britain, France, Germany, and others, registered a draft resolution that demanded "full, unimpeded, and immediate freedom of movement" for an observer mission.
It warned of "further measures" if Assad's government did not "implement visibly" the commitments made under Annan's peace plan.
'Boots on the ground'
Russia, which has stood by Damascus throughout its crackdown on an anti-government uprising, later distributed another version of the resolution, taking out the demand for "unimpeded" access and any reference to measures that could be taken if the Syrian government was deemed to be in non-compliance with the resolution.
It also took out condemnation of alleged human rights abuses in Syria.
Churkin said his country favoured a brief resolution that would get "some boots on the ground" in the form of the advance observer mission, with the mandate of the full mission to be debated later.
Annan has urged the council to call on Assad to implement all portions of his six-point peace plan that has nominally been accepted by the government and parts of the opposition.
Annan's plan includes, among other things, the requirement that troops and heavy weapons be withdrawn from Syria's cities in order to curb the government crackdown.
The rival resolutions authorise the deployment of up to 30 unarmed military observers. The UN eventually wants at least 200 monitors in the country where it says more than 9,000 people have been killed in the past 13 months.