BEIRUT A Syrian warplane flattened a three-story building, suspected rebels detonated a deadly car bomb and both sides traded gunfire in several hotspots across the country Saturday, activists said, leaving a U.N.-backed holiday truce in tatters on its second day.
The unraveling of the cease-fire marked the latest setback to ending Syria's civil war through diplomacy. Foreign military intervention is unlikely, raising the grim prospect of a drawn-out war of attrition between President Bashar Assad and those trying to topple him.
The proposed four-day truce during the Muslim holiday of Eid al-Adha had been a long shot from the start since international mediator Lakhdar Brahimi failed to get solid commitments from all combatants. Fighting dropped off in the first hours of the cease-fire Friday, but by the end of the day, activists said 151 people had been killed in bombings and shootings, a standard daily toll in Syria.
On Saturday, the first regime airstrike since the start of the truce reduced a three-story building in the Arbeen suburb of the capital, Damascus to rubble, killing at least eight men, said the Britain-based Syrian Observatory for Human Rights, which compiles reports from activists.
In the remote eastern town of Deir el-Zour, assailants detonated a car bomb near a military police compound, then opened fire at those rushing to the scene, killing a total of eight people and causing extensive damage, the Observatory said. Syrian media denied there were casualties. The attack bore the hallmarks of Jabhat al-Nusra, a radical rebel-allied Islamic group that has rejected the cease-fire.
The Syrian air force also bombed rebel positions Saturday during a fierce battle for control over the main road linking Aleppo, Syria's largest city, with the capital, activists said. Earlier this month, rebels seized Maaret al-Numan, a town along the highway and besieged a nearby military base, disrupting regime supplies to embattled Aleppo. The Syrian air force has responded with sustained bombing raids on area villages.
By nightfall Saturday, at least 49 people had been killed across Syria, including 16 Syrian soldiers, activists said. The Observatory reported deadly regime shelling and sniper attacks in several locations, while Syrian state-media said rebels ambushed a number of military positions.
Military analyst Joe Holliday said neither side has an incentive to halt fighting, noting that rebels have disrupted regime supply routes to the northern provinces of Aleppo and Idlib. "The regime can't accept the current military status quo without a fight and the rebels have no reason to since they believe they have the momentum," said Holliday, a researcher at the Institute for the Study of War in Washington.
Brahimi's spokesman declined comment Saturday on the apparent failure of his initiative. It's not clear what Brahimi's next move could be, since the international community is divided over the Syria conflict that erupted 19 months ago.
Assad allies Russia and China have shielded the regime against harsher U.N. Security Council sanctions, while the rebels' foreign backers have shied away from military intervention.
The U.S., meanwhile, is averse to sending strategic weapons to help the rebels break the battlefield stalemate, fearing they will fall into the hands of militant Islamists, who are increasingly active in rebel ranks. The al Qaeda-inspired Jabhat al-Nusra, for example, is believed to be on the front lines in Aleppo and near Maaret al-Numan.