Updated at 2:30 a.m. ET
(AP) BEIRUT - Opposition activists said Syria's uprising hotspots were quiet after a deadline for a U.N.-brokered truce passed at dawn Thursday, hours after President Bashar Assad's regime promised special peace envoy Kofi Annan it would halt fighting.
It was the first brief lull after weeks of escalating attacks on opposition strongholds.
Still, expectations were low for an abrupt end to the bloodshed that has roiled Syria for 13 months and claimed more than 9,000 lives. Syria has backtracked on previous peace plans, has characterized the uprising it's facing as a terrorist plot and has escalated the shelling of rebellious areas in recent weeks.
The regime also set an important truce condition when it announced Wednesday it would halt the fighting saying it still has a right to defend itself against the terrorists that it says are behind the country's uprising.
Under Annan's plan, the cease-fire is to be followed by the deployment of an observer mission and negotiations between Assad's government and the opposition on a political transition.
Opposition activists said the 6 a.m. Thursday truce deadline passed without reports of major violence.
Rami Abdul-Rahman, who heads the Britain-based Syrian Observatory for Human Rights, said all of Syria's flashpoints in the central provinces of Hama and Homs, the northern regions of Idlib and Aleppo, the capital Damascus and its suburbs, as well as Daraa to the south and Deir el-Zour to the east were quiet.
"Nothing is happening in these hotspots so far," said Abdul-Rahman, referring to the areas that have witnessed intense attacks by government forces and clashes between troops and defectors over the past few weeks.
In the city of Homs, activist Tarek Badrakhan said no explosions or shelling were heard since 10 p.m. Wednesday, but that army vehicles were still in the streets on Thursday. Badrakhan said nights are usually quiet, with shelling resuming in the mornings, and that it was too early to judge whether attacks had been halted.
Homs has been battered by daily shelling for the past three weeks.
The Observatory said some shots were fired in the Damascus neighborhood of Qadam after midnight Wednesday and that an explosion went off in a car in a Damascus suburb, causing no injuries. Fares Mohammed, an activist in the Damascus suburb of Zabadani, said an army tank at a checkpoint fired three shells at a nearby open area between 5:50 a.m and 6:10 am. Thursday.
The rebel Free Syrian Army, a fighting force determined to bring down Assad, has said it will abide by the cease-fire. But the opposition is not well organized, and there are growing fears of groups looking to exploit the chaos.
A cease-fire could pose a major risk for the Assad regime.
Many activists predict that huge numbers of protesters would flood the streets if Assad fully complies with the agreement and pulls his forces back to barracks. But Syria has ways to maintain authority even without the military, in the form of pro-regime gunmen called "shabiha" and the fiercely loyal and pervasive security apparatus.
Over the course of the uprising, the military crackdown succeeded in preventing protesters from recreating the fervor of Egypt's Tahrir Square, where hundreds of thousands of people camped out in a powerful show of dissent that drove longtime leader Hosni Mubarak from power.
On Wednesday, the White House cautioned that the Assad regime has reneged on promises to stop the violence in the past.
"What is important to remember is that we judge the Assad's regime by its actions and not by their promises, because their promises have proven so frequently in the past to be empty," White House spokesman Jay Carney told reporters in Washington.
Annan is scheduled to brief the U.N. Security Council on Thursday by videoconference from Geneva.
Western powers have pinned their hopes on Annan's plan, in part because they are running out of options. The U.N. has ruled out any military intervention of the type that helped bring down Libya's Muammar Qaddafi, and several rounds of sanctions and other attempts to isolate Assad have done little to stop the bloodshed.
"The West or Arab states have very little leverage over Syria, and the one thing which would certainly weaken the regime which is some form of military intervention is the one policy that is not being considered," said David Hartwell, senior Middle East analyst at the defense and intelligence group IHS Jane's.
Saudi Arabia and Qatar have called for arming the rebels, but even if they follow through there is no guarantee that such efforts could cripple Assad's well-armed regime.
Asked what steps the U.S. could take if the deal collapses, Carney, the White House spokesman, cited humanitarian and other non-lethal assistance and further sanctions.
The conflict is among the most explosive of the Arab Spring, in part because of Syria's web of allegiances to powerful forces including Lebanon's Hezbollah and Shiite powerhouse Iran.