DAMASCUS (Reuters) - From the center of Damascus, Syrians can see the shrouds of smoke rising overhead and feel the shake of explosions that warn of a frontline creeping ever closer.
The same squares where President Bashar al-Assad once drew tens of thousands to cheer in support lie empty and walled off by concrete barriers up to two meters (six feet) high.
Damascus is bracing itself after nearly two years of civil conflict as rebel forces seep deeper into the capital, and anxiety is etched across the faces of people in the city center.
"There is fear and pain in people's hearts, a feeling of despair and paralysis because of the enormity of the crisis," said Suad, an architect in the Salihiya neighborhood. "The sounds of all the different explosions - mortar, artillery and warplanes - suggest the frontline is getting closer," she said.
This ancient city has survived conquests down the ages, from Alexander the Great to early Arab caliphs and Crusaders. Sacked by Mongol invaders in 1400, it was later taken by the Turks and seized more than once by European armies last century. Now Damascus is under attack again, this time by its own people.
On Sunday, warplanes raided the Palestinian refugee district of Yarmouk, one of the most densely populated parts of the capital, where concrete homes are piled upon each other. The air strike, believed to have killed 25 people, was the closest yet to the city center, little more than a mile away.
The army warned Yarmouk's impoverished Syrian and Palestinian residents to flee in preparation for a "cleansing" operation, as bombardment ratchets up the intensity of a week of internal clashes between Palestinians for and against Assad.
Late on Monday, rebels said they had taken control of the camp, while government forces massed on its northern edge.
A new wave, thousands-strong is now seeking refuge. They are the latest victims of violence that has already forced people to flee many suburbs around Damascus, as rebels tighten their grip on the eastern outskirts of the city and its southern districts.
Um Hassan's family is fleeing for the third time in months. They fled two sieges of other rebel-held suburbs. Now their new rented apartment in Yarmouk is under fire: "Once again, I have to move. I really don't know when this will end," she said.
"God help us."
NO SAFE PLACE
Assad has support in Damascus - among fellow Alawites who fear collective retribution if he falls and also from Christians worried by radical Sunni Islamists among the rebels. Many Damascenes from the Sunni majority long, too, for a return to stability and fear Assad's departure would usher in only chaos.
Others pray he will flee, in the hope that will end the war.
Whatever their political views, civilians are putting safety first. Families and friends with homes in more central parts of Damascus have been taking in beleaguered refugees. But there are signs that generosity may be reaching its limits.
"I have moved into my parents' house along with all my siblings' families. My wife's house is full of her aunts and uncles. Who has room now?," said Issam, a resident of central Damascus. "Most families I know are like this, and I want to know what will happen to the refugees who come now."
Walking to his parents' house from work this week, he thinks some of the new homeless have found an answer: "In some shopping districts, the shutters that cover storefronts aren't locked.
"If you look inside, you can see whole families have moved inside. They can't go home."
Despite the flow into the city center, still relatively safe, rents have dropped and some apartments are empty.
"I rent my place for 70 percent of what I used to, and that's when I can find a tenant," one resident said. "You'd think the demand should be up ... but there's a sense that no place is really safe."
Informal charity networks are springing up, though many residents who fear the ire of Assad's security forces still keep their work secret.
Wael, who has organized a weekly charity drive with a group of college students, chooses a focus for help each week: "Sometimes we do children's packages. Sometimes women's packages, sometimes men's," he said.
"This week we're going to focus on those from Yarmouk."
Syrians in the capital are quietly preparing for the worst.
Everyone wants an electricity generator as supply gets more erratic. One shop in the walled Old City said it was selling 25 machines a day. Fuel is nearly impossible to find and a cylinder of gas goes for four times the normal price at about $20.
In rebel-held eastern suburbs on the outskirts, cars ignore traffic lights. All the signals have been damaged by fighting or disabled by power cuts.
Damascus has new internal borders: Tadamun and Qadam, southern neighborhoods of the capital, are clearly in rebel control. The fighters man checkpoints, oversee bread distribution at bakeries and bring in food from rural areas nearby that are also under rebel control.
Those same rural areas are now off-limits to many displaced families who fled their homes and are not allowed back past Syrian army checkpoints.
"I don't know what happened to my home; it's in an area to the east," said Issam. "My neighbors moved to central Damascus too, and they don't know what has happened to their shops. Everyone is waiting to see what is left of their lives there."
Last week, a civilian plane flew over - a rare sight since fighting engulfed the roads leading to the airports - and gave a rare spark of hope for some, like Khaled, an office worker.
He prays next time it will be a plane taking Assad off into exile: "People hope they will wake up one day and see he has fled the country peacefully."
(Writing by Erika Solomon; Editing by Alastair Macdonald)