Syria wants 'written guarantees' from opposition
Syria's government wants "written guarantees" from the opposition before it withdraws its troops from flashpoints in parts of the country.
Peace envoy Kofi Annan had not yet supplied agreements in writing from "armed terrorist groups to stop violence in all its forms", it said.
The statement comes two days before a UN-backed deadline for a ceasefire.
The leader of the rebel forces has refused to agree to Damascus's demands, the Associated Press reports.
Colonel Riad al-Asaad, commander of the rebel Free Syrian Army, said his group did not recognise President Bashar al-Assad's government and therefore would not give guarantees.
He told the AP by telephone that rebel soldiers would lay down their arms if the government in Damascus abided by Mr Annan's peace plan.
Earlier, in a statement from his office in Geneva, Mr Annan spoke of his "shock" at the recent escalation in bloodshed but did not directly mention the Syrian foreign ministry statement.
Saturday saw some of the deadliest violence yet in the year-long uprising with as many as 160 people killed.
Major new offensives are being reported by activists in the central city of Hama, the north-west province of Idlib and Aleppo, a province in the far north.
Under Mr Annan's six-point plan - which received UN approval last week - all parties are expected to halt armed violence by 10 April, with a full ceasefire on 12 April.
But Syria's foreign ministry said on Sunday that the international community was "mistaken" in its belief that Damascus had said it would pull its troops from cities and their suburbs by Tuesday.
"Kofi Annan has until now not furnished to the Syrian government written guarantees about the acceptance of the armed terrorist groups to stop violence in all its forms, and their readiness to surrender their weapons so that state authority can spread on all territory," the statement said.
Damascus also wanted "guarantees of commitment by the governments of Qatar, Saudi Arabia and Turkey to stop financing the armed terrorist groups", it said.
The BBC's Jim Muir, reporting from neighbouring Lebanon, says it is clear that Damascus is seeking complete surrender from the opposition rather than accepting a balanced truce arrangement and then talks.
That leaves both the timeline and the whole structure of the Annan peace plan under severe doubt, he adds.
Kofi Annan said he was shocked at "recent reports of a surge in violence and atrocities in several towns and villages in Syria, resulting in alarming levels of casualties, refugees and displaced persons, in violation of assurances given to me".
"As we get closer to the Tuesday 10 April deadline, I remind the Syrian government of the need for full implementation of its commitments and stress that the present escalation of violence is unacceptable," he said in his statement.
"This is a time when we must all urgently work towards a full cessation of hostilities, providing the space for humanitarian access and creating the conditions for a political process to address the legitimate aspirations and concerns of the Syrian people."