BEIRUT (AP) -- A U.N.-brokered peace deal for Syria appeared to collapse Sunday as the government made a new demand that its opponents provide "written guarantees" to lay down their weapons before regime forces withdraw from cities, a call swiftly rejected by the country's main rebel group.
The deal, brokered by U.N. and Arab League envoy Kofi Annan, was due to take effect on Tuesday, paving the way for negotiations to end the country's year-old crisis, which the U.N. estimates has killed 9,000 people.
Annan said last week that Syrian President Bashar Assad had accepted the plan and its call for government forces to pull back from urban centers. But on Sunday Syria's Foreign Ministry spokesman, Jihad Makdessi, placed a new condition -- that the opposition agree in writing "to halt violence with all its forms and their readiness to lay down weapons."
The commander of the rebel Free Syrian Army, Riad al-Asaad, said his group was prepared to abide by the Annan agreement, but rejected the government's new unilateral demand.
The FSA does not recognize the regime "and for that reason we will not give guarantees," he told The Associated Press by telephone from his base in neighboring Turkey. He said the government should withdraw its forces to bases and remove checkpoints from streets.
Annan's deal calls for government forces to withdraw from population centers Tuesday, to be followed by a full cease-fire by both sides by 6 a.m. Thursday.
However, in recent days, Syrian forces have stepped up shelling attacks on restive towns, and activists say scores of civilians have been killed daily -- at least 100 on Saturday alone.
Annan said in a statement Sunday that "the present escalation of violence is unacceptable."
He also reminded the government "of the need for full implementation of its commitments," though it was unclear whether his statement was issued before or after Damascus imposed new conditions for complying with the truce.
The cease-fire was meant to pave the way for negotiations between the government and the opposition to end the country's year-old crisis. Street protests against Assad erupted 13 months ago, inspired by the Arab Spring's pro-democracy uprisings in the region, but the revolt has turned violent in the face of a brutal regime crackdown.
The Syrian opposition and Western leaders have expressed skepticism about Assad's intentions since the deal was first agreed to because of broken promises of the past and the recent escalation in attacks on opposition strongholds.
In explaining the regime's fresh demand, Makdessi said that Syria will not allow a repeat of what had happened during the Arab League's observer mission in Syria in January, when Assad pulled back his armed forces from cities and their surroundings, only to see rebels flood the areas vacated by government troops.
"Armed terrorist groups used this to rearm its elements and spread its authority on entire districts," Makdessi said.
Damascus-based activist Maath al-Shami said he is not surprised by the latest government stance because "whenever the regime pulls out its troops and tanks, people will march to Damascus and topple the regime. Frankly speaking, the regime will collapse if checkpoints are removed."
Annan's spokesman, Ahmad Fawzi, did not immediately return calls for comment.
On Thursday, a U.N. statement raised the possibility of "further steps" if Syria doesn't implement the six-point peace plan outlined by Annan, which Assad agreed to on March 25. The statement called on all parties, including the opposition, to stop armed violence in all forms in 48 hours after the Syrian government fully fulfills the measures.
With the deadline looming, Syrian troops on Sunday pounded restive regions in the north and center of the country a day after activists said more than 100 people were killed across Syria.
Bassem Mroue can be reached on twitter at http://twitter.com/bmroue
Aji reported from Damascus, Syria.