Syrian troops backed by Hezbollah fight rebels in Damascus suburb housing major Shiite shrine

BEIRUT — Hezbollah fighters joined Syrian forces in battling rebels in a Damascus suburb that is home to a revered Shiite Muslim shrine, in a push to secure the area around the ornate, golden domed mosque.

Protection of the Sayida Zeinab shrine has become a rallying cry for Shiite fighters backing President Bashar Assad, raising the stakes in a conflict that is increasingly being fought along sectarian lines.

The fighting in the area south of the capital is part of a wider military offensive by Assad's forces to recapture suburbs held by rebels and areas in the country's strategic heartland. Activists said violent clashes coupled with heavy artillery bombardment of the southern suburbs reverberated in the capital.

The main Western-backed opposition group, the Syrian National Coalition, warned of an impending humanitarian disaster. It said regime forces, backed by Hezbollah and Iraqi Shiite fighters and dozens of tanks and armored vehicles, were besieging the area, trapping tens of thousands of civilians under heavy bombardment.

"Civilians in this area live in grim fear and anxiety, with no electricity and no way to escape from the anticipated large scale massacre that often follows these types of regime attacks," a statement issued by the group said.

The international community has been largely unable to end the Syrian civil war, now in its third year, which has killed 93,000 people, and likely many more, according to the United Nations.

President Barack Obama, Russian President Vladimir Putin and other leaders of the Group of Eight industrial economies meeting in Northern Ireland this week tried to narrow sharp differences between Russia, a key Assad backer, and Western leaders who support the rebels, but could not agree on whether Assad must go.

Speaking in Berlin on Wednesday, Obama refused to be drawn about how the U.S. might supply the rebels.

"I cannot and will not comment on specifics around our programs related to the Syrian opposition," he said. "We want a Syria that is peaceful, non-sectarian, democratic, legitimate, tolerant. ... We want to make sure that chemical weapons are not used, and that chemical weapons do not fall into the hands of people who would be willing to use them."

He said there is a need for a policy that "isolates extremists who have incorporated themselves into the opposition forces inside of Syria," an apparent reference to the al-Qaida-linked al-Nusra Front, one of the rebels' most effective fighting units.

Obama said some of his critics have become "over-cranked" about the U.S. getting involved in another war. "What we want to do is end a war," he said, through a political transition.

The Syrian war is increasingly pitting Sunni against Shiite Muslims and threatening the stability of Syria's neighbors.

The area surrounding the Sayida Zeinab suburb, about 16 kilometers (10 miles) south of Damascus, has seen fighting before. But the regime forces and Hezbollah fighters launched an intensified assault there on Monday, according to Rami Abdul-Rahman, the director of the Syrian Observatory for Human Rights.

The assault appears aimed at decisively pushing rebels back and securing the suburb, home to the shrine of Sayida Zeinab, the Prophet Muhammad's granddaughter. Before the war, the shrine attracted tens of thousands of Shiite pilgrims from around the world. Last year, rebels kidnapped Iranian pilgrims visiting the area, accusing them of being spies. The pilgrims were later released.

Hezbollah leader Sheik Hassan Nasrallah has called it "a duty" to protect the shrine, saying that its destruction by extremists among Syrian rebel ranks would ignite a sectarian war with no end.

State TV said government forces were able to clear rebels out of one adjacent neighborhood, al-Bahdaliya. Meanwhile, rebel forces claimed they took control of the Khomeini hospital in a village south of the shrine, from which they were battling regime forces and allied militias. They said they inflicted losses among the ranks of Hezbollah fighters and regime troops in the area.

Opposition fighters control several suburbs of the capital, threatening the heart of the city, the seat of Assad's power. But the regime has largely been able to keep them at bay.

U.S. officials estimate that 5,000 Hezbollah militiamen are fighting alongside the regime, while thousands of Sunni foreign fighters are also believed to be in Syria — including members of Jabhat al-Nusra, an al-Qaida affiliate that is believed to be among the most effective rebel factions,

Hezbollah fighters were instrumental in a recent victory for regime forces, regaining control of the strategic town of Qusair in central Homs province after it was in rebel hands for more than a year.