It may be time for the world to acknowledge that a cease-fire is not holding in Syria, and that it is time to try another approach to stop the violence, the White House said Thursday.
"If the regime's intransigence continues, the international community is going to have to admit defeat," White House press secretary Jay Carney said.
It was the clearest statement yet that the Obama administration sees little chance for the cease-fire and peace plan brokered by United Nations envoy Kofi Annan last month but largely ignored by Syrian forces loyal to President Bashar Assad.
"It is clear and we will not deny that the plan has not been succeeding thus far," Carney said.
The Annan plan has done little to stem the bloodshed, but so far other nations that back it have been unwilling to say it is dead.
U.S. officials have said the plain is failing because of Syrian government violations.
The Assad government and the Syrian opposition are blaming one another for torpedoing the truce, with Assad's forces trying to repress demonstrators calling for him to step down. The regime also is facing an armed rebellion that has sprung up as peaceful protests have proved ineffective against his forces.
The United States was skeptical of the Annan program from the start, fearing that it lacked teeth and might lead to an easing of international pressure on Syria. The U.S. has publicly backed the plan, however, and Carney did so again Thursday.
The spokesman said that if the Syrian regime keeps flouting the cease-fire, the United States and other nations should try other measures to pressure Assad. Carney said that would include a return to the U.N. Security Council, which approved an observer mission in Syria last month, and other attempts to marshal international pressure. He did not say what that entails.
Secretary of State Hillary Rodham Clinton is on record supporting a U.N. arms embargo and a ban on overseas travel by senior members of the Syrian regime. Those or other harsh measures are almost certain to face a veto from Russia, Syria's principal ally at the Security Council, at least until the three-month observer mission ends.
The U.S. is not considering a military intervention in Syria now.
Annan, the joint U.N.-Arab League envoy, is scheduled to brief the Security Council on Tuesday with the latest assessment on implementation of his six-point peace plan.
Syrian forces stormed student dormitories during an anti-government protest at Aleppo University on Thursday, firing tear gas and bullets in an hours-long siege that killed at least four students and forced the closure of the state-run school, activists said.
U.N. truce observers toured other restive parts of the country, and residents told them of being too terrified to walk on the streets after dark as the 14-month uprising rages on. The U.N. estimates 9,000 people have been killed since the revolt began.
The head of the U.N. observers, Norwegian Maj. Gen. Robert Mood, visited the central cities of Homs and Hama, where anti-regime sentiment runs high. He said there is still "a good chance and an opportunity" to break the cycle of violence.
"I call on all the parties to stop the violence," Mood told reporters. "If you use military force, it creates more force, it creates more violence ... so it should always be the last resort."
Associated Press writer Edith M. Lederer at the United Nations contributed to this report.