Syria said on Sunday, ahead of a UN deadline, that its forces will not withdraw from protest hubs without written guarantees, as the main opposition group urged UN intervention after one of the deadliest days in a year.
As Tuesday's deadline loomed for regime forces to cease fire and pull back from rebel cities, the foreign ministry said it had not been given assurances that "armed terrorist groups" would also put down their guns.
"To say that Syria will pull back its forces from towns on April 10 is inaccurate, Kofi Annan having not yet presented written guarantees on the acceptance by armed terrorist groups of a halt to all violence," it said.
On Thursday, the UN Security Council formally endorsed the deadline for Syrian troops and big guns to be withdrawn from cities, but Damascus said a day later the number of "terrorist acts" has risen since the deal was agreed with UN and Arab League envoy Annan.
"Mr Annan has not submitted written guarantees from the governments of Qatar, Saudi Arabia and Turkey on stopping their funding to terrorist groups," the ministry added of its northern neighbour and strongest critics in the Arab world.
Annan's peace plan foresees the withdrawal of the Syrian army from protest cities on Tuesday, with a complete end to fighting 48 hours later.
"Syria is not going to repeat what happened in the presence of Arab observers when armed forces left towns," Sunday's ministry statement said.
"Armed terrorist groups reorganised and rearmed to control entire neighbourhoods, committing every possible terrorist act, killing and kidnapping people and destroying public and private property."
The ministry said that when Annan met President Bashar al-Assad in Damascus, the former UN chief "said he would work to stop the violence, disarm armed groups ... initiate a comprehensive national dialogue with opposition movements."
"It is this principle on which Syria accepted Annan's mission and his six-point plan."
However, the ministry also expressed the government's willingness to cooperate, "and we will continue to inform him of the steps we are taking to implement the plan, in the hope of obtaining documented guarantees."
The main umbrella opposition group the Syrian National Council called for UN intervention after monitoring groups said 86 of nearly 130 people killed on Saturday were civilians.
"We urge the UN Security Council to intervene urgently to stop the humanitarian crisis caused by the regime against the unarmed Syrian people, by adopting a resolution under Chapter 7 to ensure the protection of civilians," the SNC said.
It said that "to believe in the promises of this barbaric regime enables it to advance its criminal plan of tearing Syria apart and bathing it in blood."
"The regime has committed savage massacres that killed nearly 1,000 people since it falsely announced the acceptance of the plan" put forward by Annan.
On Saturday alone, at least 40 civilians died "in bombardment and shooting on the town of Latamna," in Hama province, said the Britain-based Syrian Observatory for Human Rights.
Five civilians were killed in Tibet al-Imam, also in Hama, while another 18 died in the neighbouring province of Homs, where Rastan town was bombed, 22 in Idlib to the northwest and one in Aleppo in the north.
Sixteen rebels and 26 members of the security forces were also reported killed nationwide.
Annan had warned of "alarming" casualties as the Syrian government's year-long crackdown on dissent -- which the United Nations says has killed more than 9,000 people -- showed no signs of abating.
Monitors put the number of dead at more than 10,000.
Sunday's SNC statement said that both it and the rebel Free Syrian Army, "have announced their cooperation with the Annan plan and international efforts to halt the bloodshed and launch a political way to transfer power from the hands of Assad and his clan to the Syrian people."
Ban said on Friday that the increased attacks by Assad's forces on cities "violate" a UN Security Council statement demanding an end to hostilities by Tuesday's deadline.
He indicated that he believes Assad's government is using the deadline to pull troops and heavy weapons away from cities as "an excuse" to step up the killing.
Ban "deplores the assault by the Syrian authorities against innocent civilians, including women and children, despite the commitments by the government of Syria to cease all use of heavy weapons in population centres," said his spokesman Martin Nesirky.
"The April 10 timeline to fulfill the government's implementation of its commitments, as endorsed by the Security Council, is not an excuse for continued killing," Ban added.
The Security Council on Thursday formally endorsed the April 10 deadline, with both Russia and China, which vetoed two previous Security Council resolutions on Syria, signing up to the new demands.
Foreign Minister Walid Muallem is scheduled to travel to ally Moscow on Monday for talks on the crisis.