The upheaval that has roiled much of Syria for the past 10 months is seeping its way into the heart of the country’s capital, puncturing the sense of invulnerability that had until recently sustained confidence in the government’s ability to survive the revolt.

On Sunday, security forces launched a major assault to reclaim suburbs just a short drive from the city center that had fallen under the sway of rebel soldiers fighting under the banner of the Free Syrian Army.

The sound of gunfire and shelling from a string of suburbs on the eastern edge of the city could clearly be heard in several central neighborhoods, residents said, bringing perilously close a conflict that had until recently been dismissed as a mostly rural, provincial phenomenon from which Damascus, President Bashar al-Assad’s stronghold, would remain immune.

Activists said at least 10 people died in the offensive, among 32 killed Sunday across Syria as the government steps up its efforts to crush what is now, unmistakably, an armed revolt.

In one indicator that those who had once engaged in overwhelmingly peaceful protests now are fighting back, the official news agency, SANA, reported the funerals Sunday of 23 soldiers and police killed in the violence, as well as an attack on a bus in the Damascus suburb of Sahnaya in which six soldiers died.

Those deaths bring into the hundreds the number who have died in the past three days as the Syrian revolt, which threatens to become the bloodiest and most profound of all those in the region over the past year, appears to be lurching into a new and more dangerous phase.

With the crisis closing in on the capital, a siege mentality is starting to take hold. Roads leading out of Damascus no longer are deemed safe because of the threat of ambush, and stories of bandits stalking the hills surrounding the city further add to the anxiety.

“We are surrounded,” said a prominent Syrian journalist, who asked not to be named because of the sensitivity of the subject. “We can’t drive north. We can’t drive south. We can only go west, to Lebanon.”

“What’s happening is obvious,” the journalist said. “You can see it. It’s civil war. Everyone’s trying to deny it but you can’t hide from it.”

Out of mind no more

For months, many Damascenes attempted to tune out the unrest unfolding largely out of sight of their city’s trendy cafes, upscale malls and traffic-clogged streets, aided by a government intent on convincing the world that an uprising cast as a foreign plot would be vanquished.

A recent visit to the city made clear the extent to which the revolt can no longer be ignored.

The power is off for two, or four, or six hours a day, depending on the wealth and loyalty of the neighborhood. The Syrian pound, which mysteriously sustained much of its value for many of the previous months, has plunged past the psychologically significant barrier of 70 to the dollar, from around 50 for much of the past year.

Prices are soaring, fuel is scarce, and lines form at gas stations as sanctions imposed by the United States and the European Union take their toll on the economy.

A string of recent bombings targeting the security forces did more than anything else to burst the bubble. Concrete barricades have been erected around key security agencies and the homes of top officials, while soldiers in flak jackets and helmets peer out from sandbagged positions around important government facilities.

With fighting taking place within earshot of the president’s home and rumors flying of fresh defections within the ranks of the security forces, the government is looking weaker than at any point during the past 10 months, analysts say.

“We might be seeing that the regime is weaker than we thought,” said Salman Shaikh, director of the Brookings Doha Center in Qatar, who fears that a full-blown conflict could spill across the region before the international community has figured out a way to respond to the crisis. “The diplomacy is struggling to keep up with what’s happening on the ground,” he said.

Activists on Sunday said they feared a civilian bloodbath, with Assad’s forces intent on asserting their control by any means to preempt possible action this week at the U.N. Security Council. An Arab League mission to monitor the violence was suspended on Saturday because of the deteriorating security conditions, intensifying pressure on the wider international community to adopt a tougher response.

But diplomats and analysts here question whether the regime has the capacity to crush a revolt that is now encircling the capital.

In recent weeks, efforts by government forces to wrest back territory, in the violence-racked city of Homs and elsewhere across the increasingly uncontrollable north of the country, have contributed to a surge in bloodshed — but not yet a reversal of the rapidly encroaching armed insurgency.

Assad still holds the loyalties of the security forces, particularly the officer corps drawn mostly from his own Alawite sect. Diplomats in Damascus suspect, however, that defections among the rank and file are accelerating faster than had previously been thought, as soldiers deployed without leave on low pay for nearly a year find themselves drawn to the revolt.

A cease-fire agreement under which security forces were forced to withdraw from the town of Zabadani, 20 miles west of Damascus, leaving it in the hands of the Free Syrian Army, came about in large part because the government feared soldiers would defect in large numbers if they were forced to keep attacking the city, according to activists in the town and diplomats.

“In Syria, looking weak is a dangerous thing, and if they can’t control the Damascus suburbs, they do look weak,” said a Western diplomat.

‘No one can protest here’

In the souks of old Damascus, where some of the first protests last year were quickly suppressed, the talk is not of when the revolt will end but how bloody it will get — and what the finale will look like. According to the whispered confidences of merchants, support for Assad is eroding, and only fear of the pervasive security forces is deterring city residents from joining in the revolt.

“No one can protest here,” said a man selling head scarves in the Midhat Pasha section of the souk. “Damascus is not like the rest of the country. Here the government is so strong. It is a security government.”

But, he added, “people are so angry. It will come soon to Damascus.”

“I used to be pro, but now I’m not,” said another merchant, selling children’s clothes deep in the warren of narrow alleyways where stall owners lament that they haven’t had customers for weeks. “But you can’t say you support the opposition or you will be arrested.”

Assad can still count on support within Damascus, notably among the wealthy elite and the sizable minority belonging to the Alawite and Christian sects who worry they would be persecuted under a government controlled by the Sunni majority.

No longer do his staunchest loyalists sound quite so confident that the government will prevail, however.

“Really it’s very, very scary what is happening,” said Samer, a 28-year-old banker, who is Alawite, as he sipped beer in a bar in the Christian quarter of the walled old city. “We are heading into the unknown.”