The US Ambassador to the United Nations, Susan Rice, has warned Syria not to intensify violence in the days leading up to a ceasefire proposed by the UN and Arab League.
Ms Rice said the UN Security Council must respond urgently if Syria fails to keep its pledge to end military operations by next Tuesday.
Activists say the Syrian government is stalling for time so it can crush the uprising before international monitors arrive.
Fierce clashes erupted after Syria's regime sent reinforcements into rebel areas despite the truce pledge.
The surge in violence yesterday killed at least 38 people, including 25 civilians, mostly in north and central Syria, and saw a string of arson attacks on homes, activists and monitors said.
The Syrian Observatory for Human Rights has claimed that the army is burning and looting rebel houses across the country in a campaign that could amount to crimes against humanity.
Reports from Syria cannot be independently verified as state authorities have barred international journalists and rights groups.
Earlier this week, peace envoy Kofi Annan told the UN Security Council that President Bashar al-Assad had given assurances he would "immediately" start pulling back his forces and complete a military withdrawal from urban areas by 10 April.
The US has accused Mr Assad of failing to honour his pledged troop withdrawal, as monitors reported heavy fighting in opposition strongholds in the southern region of Deraa, the central city of Homs, northwestern Idlib province and near the capital.
With international concern at the situation growing, a draft UN Security Council statement was drawn up asking Syria to respect the deadline to halt its military operations in protest cities, according to a copy of the text seen by AFP news agency.
The draft also urges the Syrian opposition to cease hostilities within 48 hours after the Assad regime makes good on its pledges.
It also calls on all parties to respect a two-hour daily humanitarian pause, as called for in Mr Annan's plan.
Negotiations on the text, distributed by Britain, France and the United States, began yesterday.
