BEIRUT - Syrian rebels killed at least 80 army soldiers in a surge of attacks at the weekend, an opposition watchdog said on Monday, carrying out their threat to resume fighting if President Bashar al-Assad failed to observe a U.N.-backed ceasefire.
The May 25 massacre of at least 108 people, nearly half of them children, in the Houla area of Homs province dealt a possibly fatal blow to envoy Kofi Annan's proposed ceasefire, which was supposed to take effect on April 12 but never did.
A Free Syrian Army spokesman said the rebels were no longer bound by the truce after their Friday deadline passed.
"We have decided to end our commitment to this (ceasefire)," Major Sami al-Kurdi, told Reuters from Syria, adding that rebels had begun attacking government forces to "defend our people".
He said a U.N. observer mission should be turned into a "peace-enforcing mission", or that the world should impose a no-fly zone and a buffer zone to help bring Assad down.
Such ideas have gained little traction previously with Western powers, letalone their Russian and Chinese critics.
The latest violence and a defiant speech by Assad on Sunday raised questions about how long Annan can pursue his threadbare peace plan on behalf of the United Nations and the Arab League.
But U.N. Secretary-General Ban Ki-moon told Reuters Annan's mission "remains central" to resolving the Syrian crisis.
The Syrian Observatory for Human Rights said local doctors had confirmed the names of 80 dead government soldiers.
Insurgents told the British-based group they had killed more than 100 soldiers and destroyed some tanks in clashes across Syria, including Damascus and Idlib province in the northwest.
Syria's state news agency reported the burial on Monday of 30 members of the security forces killed by rebels.
A Syrian troop pullback was at the top of Annan's six-point plan to halt hostilities, allow peaceful protests, supply humanitarian aid and start a political transition in a country controlled by the Assad family with an iron fist for 42 years.
RUSSIA, CHINA ADAMANT
"The Annan mission is essentially dead, and of course most Western powers admit that," said Michael Stephens, researcher at the Royal United Services Institute's branch in Qatar.
"Houla changed the game completely in terms of what people were willing to accept and what they were not."
However, Russia and China, wary of any Western-led military intervention in Syria, say Annan's plan is the only way forward. They have twice blocked U.N. Security Council resolutions which would have condemned Damascus and perhaps led to sanctions.
Western powers have no appetite for Libya-style military action, but have provided no alternative to Annan's efforts.
Assad has rebuffed criticism of the carnage in his country. "When a surgeon performs an operation to treat a wound, do we say to him: 'Your hands are covered in blood'?" he asked in his speech on Sunday. "Or do we thank him for saving the patient?"
Annan, who has inserted 300 U.N. observers into Syria to verify the non-existent truce, will brief the Security Council on Thursday. A U.S. official said the envoy would see Secretary of State Hillary Clinton in Washington the next day.
Ban, speaking on the sidelines of an Islamic Development Bank meeting in Jeddah, urged Assad's government to stop the violence immediately "in the name of humanity" and to start a political dialogue with his foes.
"We are deeply troubled by what has been going on," the U.N. chief told Reuters. "Annan's plan remains central to the resolution of the Syrian crisis."
U.N. diplomats in New York say it is not clear whether the Security Council will renew the increasingly risky U.N. observer mission to Syria when its 90-day mandate expires around July 20.
Arab League chief Nabil Elaraby has asked the Security Council to expand the size and beef up the force's mandate, but one diplomat said council members saw many risks involved in that idea, which the Syrians were anyway unlikely to accept.