UN peace envoy Lakhdar Brahimi said today the Syrian government and "some rebel leaders" had agreed to a ceasefire during Muslim holiday Eid.
But Syrian officials said the envoy's proposals were "still being studied" by the military high command and the government would not come to a decision until tomorrow.
Mr Brahimi did not explain who would monitor any ceasefire. and it was unclear whether the army would agree to hold its fire for four days when there is no single rebel organisation which could enforce a ceasefire on all opposition fighters.
And he declined to confirm he had a "commitment" from rebels to lay down their arms when Eid begins on Friday, saying only that he had "promises."
Fighting continued to rage unabated today, with rebels reporting air strikes on the village of Mar Shureen and shelling in towns across the country.
The envoy's plan is modest compared with the six-point plan for peace proposed by his predecessor, ex-UN secretary-general Kofi Annan.
But it may still fail due to the complete lack of trust between the two sides in Syria's civil war.
The Annan ceasefire was not adhered to by either the government or the rebels, and both accused each other of having breached it first.
The Syrian National Council - a self-styled government in exile - said it had little hope the truce would hold.
The council holds very little influence over the largest armed group the Free Syrian Army and none over the numerous al-Qaida-linked groups operating in the country.