A statement from Syria's Foreign Ministry said U.N. peace envoy Kofi Annan had "not yet presented written guarantees on the acceptance by armed terrorist groups of a halt to all violence," the BBC reported Sunday.
Additionally, the statement said Annan has failed to offer guarantees that Qatar, Saudi Arabia and Turkey will stop funding and arming the opposition groups, Syrian government news agency SANA reported.
All parties would halt armed violence by Tuesday and a full cease-fire would take effect Thursday under Annan's six-point plan, the BBC reported.
Meanwhile, at least 127 people were killed Saturday in Syria, Local Coordination Committees of Syria, a group of opposition activists, told CNN.
The group said Syrian forces have been targeting villages where fighting had already displaced residents.
One LCC activist who identified himself as Saleem, said he saw the tortured bodies of 13 people, including youths, outside a school in Homs.
"The truth is we have become used to such massacres. We have seen people beheaded, children killed, bodies torn apart, and nothing surprises us anymore," Saleem told CNN. "All we could do is pray to all for help and call on the world to intervene."
The United Nations estimates more than 9,000 people have been killed in the yearlong uprising against Syrian President Bashar Assad. The LCC puts the toll at more than 11,000. Another 1 million people need humanitarian aid inside the country and tens of thousands have been displaced.