Syrian warplanes bombed a building in a Damascus suburb on Saturday, killing at least eight people in the first airstrike since an internationally mediated ceasefire went into effect, activists said.

The attack came a day after car bombs and clashes left 151 dead, according to activist tallies, leaving the four-day truce that began Friday at the start of a major Muslim holiday in tatters. The Britain-based Syrian Observatory for Human Rights reported that eight people were killed and many others wounded in Saturday’s airstrike in Arbeen.

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 late Saturday, at least 76 people had been killed across Syria, including 20 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.

In the north, rebels and Kurdish neighborhood guards fought a rare battle late Friday in the embattled city of Aleppo that left 30 people dead, activists said.

“The ceasefire collapsed nearly three hours after it went into effect,” said Rami Abdul-Rahman, who heads the Observatory.

“This is a failure for Brahimi. This initiative was dead before it started,” Abdel Jabbar al-Okaidi, the head of the Free Syrian Army military council in the northern city of Aleppo, told AFP by telephone.

Al-Okaidi put the blame squarely on the shoulders of President Bashar Assad’s regime and insisted that the rebels had not broken the ceasefire.

“I was on several fronts yesterday and the army did not stop shelling,” he said. “Our mission is to defend the people. It is not us who are attacking.”

The Observatory for Human Rights also said 30 rebels and Kurdish gunmen were killed in clashes that broke out in Aleppo’s predominantly Kurdish neighborhood of Ashrafieh late Friday. A Kurdish official put the death toll at 10 Kurds, but had no figures for the rebels.

Rebels made a push Thursday into largely Kurdish and Christian areas that had been relatively quiet during the three-month battle for Syria’s largest city.

Kurds say the rebels had pledged to stay out of their neighborhoods. Kurdish groups have for the most part tried to steer a middle course in the conflict between the rebels and the regime of President Bashar Assad.

Mohieddine Sheik Ali, head of the Kurdish Yekiti party, said the clashes broke out after rebels entered Ashrafieh, violating “a gentlemen’s agreement” not to go into Kurdish areas in Aleppo.

He said 100,000 Kurds live in Ashrafieh and many in the nearby Sheik Maksoud area. Sheik Ali said tens of thousands of Arabs have also fled to these areas to escape the violence in other parts of Aleppo.

The Observatory said the clashes led to a wave of kidnappings between the two groups, but did not provide further details. Pro-government news websites also reported the clashes.

Kurds are the largest ethnic minority in Syria, making up around 10 percent to 15 percent of the country’s 23 million people.

After the anti-government uprising began in March last year, both the Syrian government and opposition forces began reaching out to the long-marginalized minority whose support could tip the balance in the conflict.

Kurds have long complained of neglect and discrimination. But they are also leery of how they would fare in a Syria dominated by the large Sunni Arab rebel movement

In other violence, the Observatory and the Local Coordination Committees also reported shelling and shooting Saturday in Aleppo and Daraa to the south.

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.

Shadi Hamid of the Brookings Doha Center said the truce at least “provides the illusion of movement, that something is being done, that the international community is still trying to find a solution.”

The U.S. said Friday that both sides have violated the holiday cease-fire, but singled out the regime. In the previous attempted truce six months ago, the Syrian military violated key provisions, such as withdrawing troops from urban centers, and was widely held responsible for the collapse of the cease-fire.

Syrian Foreign Ministry spokesman Jihad Makdessi on Saturday accused the U.S. of being one-sided. He said Syria remains committed to halting military operations. He said all cease-fire violations were the result of attacks, most of them carried out by organizations that originally rejected the truce, an apparent reference to Jabhat al-Nusra. The spokesman said Syria has sent messages to the U.N. Security Council concerning the violations.

In Lebanon, the leading LBC TV said Lebanese journalist Fidaa Itani, one of its employees covering Syria’s civil war, was detained by the rebels and is being held in the town of Azaz near the Turkish border.

The station quoted a local rebel leader in Azaz, Abu Ibrahim, as saying that rebels suspected Itani after he filmed many videos of rebels operations in Aleppo. Itani’s Lebanese cell phone was closed when The Associated Press tried to reach him.

The area also was the site of the May kidnapping of 11 Shiite Lebanese pilgrims who were on their way home from Iran. Two have been released while rebels say they will hold the others until Sheik Hassan Nasrallah, the leader of Lebanon’s militant Hezbollah group, apologizes to the Syrian people for supporting Assad.
A rebel commander in Aleppo said Saturday that UN-Arab League envoy Lakhdar Brahimi’s ceasefire had failed.