Manu Brabo, Associated Press
Kurdish demonstrators make their way back to their homes after a demonstration celebrating the anniversary of the death of Barzani, late Peshmerga leader in Iraq, near the town of Deriq, a Kurdish area of Syria, near the border with Iraq, Saturday, March 2, 2013.

BEIRUT, Lebanon (MCT) — Rebel forces have dug in to the north, east and south of Syria's capital, occupying stretches of suburban and rural terrain and threatening to break through to the heart of Damascus.

Government troops have largely pulled back to a well-defended core, including the city center and loyal bastions to the west.

After nearly two years of fighting in Syria that has mostly spared the capital, an uneasy stalemate reigns in Damascus. In recent days, the city has experienced mortar attacks and car bombings, while the military has responded in its usual fashion: withering bombardment of outlying rebel strongholds.

A huge explosion rocked the city Monday, apparently a car bomb targeting a checkpoint in heavily defended Abaseen Square, a potential route into the city for rebels based in the nearby Ghouta region.

Residents of Damascus are edgy, fearing that the fighting is closing in.

"I don't go anywhere unless I have specific business," said a woman in her early 50s who requested anonymity for safety's sake. "No one does."

While Damascenes wait and worry, the opposition presses foreign allies for support that could help break the impasse in the grinding conflict. On Thursday, Secretary of State John F. Kerry pledged $60 million in additional nonlethal aid during meetings with opposition figures in Rome, though he turned aside their plea for weapons.

Much of Syrian President Bashar Assad's military is focused on defending a strategic zone that includes the presidential palace, government buildings and military bases, drawing up a kind of cordon sanitaire around the capital. Checkpoints are everywhere. Reinforcements also reportedly have been dispatched to secure roads leading north to Homs and southeast to the international airport.

Damascus is crucial to both sides in the conflict, but it is only one of many battlegrounds. Analysts say the government is determined to maintain a corridor from the capital along the highway north to Homs and to the Alawite heartland on the Mediterranean coast, long mentioned as a haven for Assad and his allies should the government face collapse.

"Trying to keep that highway secure is of major strategic importance," said Joshua Landis, who heads the Center for Middle East Studies at the University of Oklahoma. Still, Landis said, "obviously, Assad thinks he can hang on to Damascus. That's key for him."