U.N.-Arab League envoy Kofi Annan says he is “encouraged” by reports that a shaky cease-fire between government troops and rebels in Syria seems to be holding, despite scattered violence.

In a briefing on Syria to the United Nations Security Council Thursday, Mr. Annan urged the Syrian government to take further steps by removing troops and heavy weapons from major population centers. Diplomats says Mr. Annan also told the Council that Syria had not fully complied with the terms of the peace plan that he brokered in March.

But Syria's envoy to the U.N. said his government had ended attacks and expected opposition militias to do the same. Ambassador Bashar Ja'afari said, “the moment of truth has come.”

He blamed anti-government forces for several violent acts that he said occurred after the cease-fire deadline, including a bombing that killed a military officer in Aleppo and two civilian deaths elsewhere in the country.

But rights activists said Syrian forces killed at least three civilians after the cease-fire dealine passed. They say the attacks took place in areas including the protest hubs of Homs and Hama.

Opposition groups also said Syrian troops remain deployed in flashpoint cities and are on high alert.

The cease-fire is being watched closely by skeptical Western envoys and Syrian opposition groups who are weighing Syrian President Bashar al-Assad's good faith in observing the agreement.

U.S. President Barack Obama and French President Nicolas Sarkozy issued a joint statement urging Syria to abide by Mr. Annan's plan. Separately, U.S. Secretary of State Hillary Clinton called a Syrian cease-fire an “important step” but urged Damascus to abide by all of the provisions of the plan.

U.N. chief Ban Ki-moon said the international community must be united if it is going to keep Syria from descending into “chaos.” Mr. Ban said plans were underway to send observers to Syria. Diplomats said the first U.N. peacekeepers could be dispatched as early as Friday.

Both China and Russia's U.N. ambassadors welcomed Mr. Annan's mediation efforts. The two nations have been among the strongest critics of foreign intervention in Syria.

The Assad government on Thursday urged thousands of Syrians who fled from their homes or took refuge in neighboring countries to return home.

One refugee staying on the Turkish side of the border told Reuters news agency nothing from Mr. Assad's government could be trusted.

“We do not trust in the words of Bashar Assad because he is a liar. His government is lying. All the countries know this.”

Refugee Huseyin Kasif at the Yayladagi Refugee Camp in Turkey also dismissed Mr. Assad's intentions, accusing him of spewing “gibberish.”

“This cease-fire will not stay long. He has been promising this for a year. I do not think he will withdraw neither tanks nor troops. He is lying. Whenever he says he will end the massacre, he kills more.''

Opposition Syrian National Council member Bassam Imadi Thursday said he was not certain the cease-fire would hold. And he said, if it did, it could only be a first step.

“There should be some kind of dialogue. In our mind, the dialogue should be about the transition phase after Assad steps down. So this could be the second step.''

U.N. officials say more than 9,000 people have been killed in Syria since the uprising began 13 months ago.