A draft resolution being considered by the U.N. Security Council would authorize a first group of up to 30 unarmed military observers to deploy to Syria to monitor a cease-fire between government forces and opposition fighters.

The draft, obtained Thursday by The Associated Press, demands that the government ensure freedom of movement for the observers and the ability to interview anyone they want in private.

It also demands that the Syrian government withdraw its troops and heavy weapons from population centers to their barracks.

If Syria does not implement its commitments, the draft expresses the council's determination "to consider further measures as appropriate."

In diplomatic terms, that could include sanctions which Russia and China, whose governments have backed Syria's government, have previously opposed.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

UNITED NATIONS (AP) _ International envoy Kofi Annan told the U.N. Security Council on Thursday he was "encouraged" at the start of a fragile cease-fire in Syria but said the government failed to keep its pledge to withdraw troops and heavy weapons from cities and towns.

U.S. Ambassador Susan Rice, the current council president, said Annan urged council members to demand that Syrian President Bashar Assad order his troops back to barracks.

She quoted Annan as saying in his video briefing to the council that "troops and heavy weapons remain in population centers."

Annan asked the Security Council to quickly authorize the deployment of an advance U.N. team to monitor the cease-fire, ahead of the deployment of a larger monitoring mission. South Africa's U.N. Ambassador Baso Sangqu said discussions on the text of a U.N. resolution authorizing the deployment would begin Thursday afternoon, and diplomats said it could be adopted as early as Friday.

U.N. Secretary-General Ban Ki-moon cautioned that a single gunshot could derail the fragile peace that started at 6 a.m. Damascus time. He urged both sides to refrain from provocation.

"It may be broken any time," Ban said. "If and when there is another gunshot, even a small gunshot may give both sides the pretext to engage in another fighting. This is a very worrisome."

Both Ban and Rice said the onus was on Syria to maintain peace.

"Its track record up until today has been dismal," Rice said. "We hope, but we clearly remain cautious in our assessment, that today becomes the start of a new way forward. But I think, frankly, we have a year's worth of evidence that leads us all to enormous skepticism."

The Assad regime has been using force to put down a civilian uprising for more than a year, and at least 9,000 people have died, according to U.N. estimates.

Syria's U.N. Ambassador Bashar Ja'afari reiterated to reporters that his government is committed to the success of Annan's mission and insisted that "we have already complied" with the requirement in his six-point peace plan to pull back troops and equipment.

But Rice countered that the Syrian ambassador was not in the Security Council chamber during Annan's closed-door briefing and did not hear the assessment of the joint U.N.-Arab League envoy. She quoted Annan as saying Syrian troops and equipment "must return to barracks as soon as possible."

Ja'afari said Syria's commitment to making the Annan plan a success must be matched by Arab, regional and international countries that are funding and arming the rebels, singling out Qatar, Saudi Arabia, Turkey and the United States.

In a statement issued before his videoconference briefing from Geneva, Annan said he was "encouraged by reports that the situation in Syria is relatively quiet and that the cessation of hostilities appears to be holding."

Rice said Annan told the council he had received unconfirmed reports of some violence in some cities after the cease-fire took effect, but said this was not unusual in the early hours of a cessation of hostilities "as parties were testing each other."

The Russian and Chinese ambassadors, whose countries have backed the Assad government, called the Syrian cease-fire an important step and said they support implementation of all points in the Annan plan _ including the troop and equipment withdrawal.

"We're encouraged that we do now have a cessation of violence in Syria," Russia's U.N. Ambassador Vitaly Churkin said. "We hope it holds. Everybody needs to behave with maximum prudence for that to happen."

He urged all countries "with influence on the parties" to help ensure that the cease-fire holds so political dialogue can start and Syria can "finally come out of this crisis."

Churkin and China's U.N. Ambassador Li Baodong said they will support the speedy deployment of U.N. monitors.

"It's crucial for the monitors to be on the ground to make sure that any transgressions of the current state of end of violence is going to be detected," Churkin said. "We are concerned at the possibility of provocations. We are concerned about the appeals for massive demonstrations. ... This is the opposite of what needs to happen now."

Li said the Chinese government has been working on the Syrian government and opposition parties, in close contact with Annan, "in order to ease tension and promote a political process."

"Progress has been made, though it's fragile, but we hope that through the joint efforts we can maintain this progress and can make more progress in the future," he said.

Annan and Ban stressed the need to get a U.N. observer force in place.

"It is difficult to fully assess the situation on the ground, in the absence of U.N. observers. And therefore we are working with the Security Council to send an observer team as promptly as possible," Ban told reporters.

Annan's spokesman, Ahmad Fawzi, has told reporters that the U.N.-backed mission would have about 200 to 250 observers and that nations were being asked to contribute soldiers.

Churkin spoke of trying to get 20-30 observers on the ground early next week.

Ban said the observer mission could get going almost as soon as it gains authorization.

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John Heilprin reported from Geneva. Peter James Spielmann contributed to this report from the United Nations.