Entire neighborhoods of Syria's largest city bear battle scars: buildings toppled by government shells, charred tanks blown up by rebels and trash-strewn no-man's lands where neither side has full control after nearly a month of deadly street battles.

Ruin and tragedy can come in an instant. On Friday, a government fighter jet blasted the top three floors of a five-story apartment building, killing a mother, father and their three boys. Buried in the rubble was a newlywed couple who moved in on their wedding night two months ago.

Rebel fighters crawled through collapsed debris and punched holes in walls while searching the building for Mohammed Ezzo, his wife Ola, and anyone else that might be there. Across the street, the groom's father gazed at the building and wailed into his hands.

"The top floor and the floor below it and the floor below that, they all fell on top of them!" cried Munir Ezzo, 70.

The destruction, witnessed by The Associated Press during a visit to the city Friday, have transformed Aleppo, a city of around 4 million that for much of Syria's 17-month-old conflict, was considered a bastion of support for the regime of President Bashar Assad. Tens of thousands — as many as 200,000 by one U.N. estimate — have fled the city.

Assad's forces are turning to attack helicopters and fighter jets to dislodge rebels who have held out through weeks of fighting and clash daily with government troops. Rebels moved into the city last month after pushing the army from most towns between the city and the Turkish border to the north, "liberating" neighborhoods from the city's northwest to its southwest corner, many of them largely Sunni Muslim districts that support the uprising.

Rebels now claim to hold more than half of the city. But very few fighters were seen in a number of opposition neighborhoods Friday, indicating that rebel "control" is tenuous at best. The army still holds much of the city's core and northwest, and its helicopters and fighter jets control the skies, forcing residents to avoid open areas or stay home.

Friday's fighting centered in the city's southwest corner and near its airport, some 15 kilometers (nine miles) southeast of the city's historic center. Syria's state news agency said that "armed terrorist groups" — regime shorthand for the rebels — had been pushed from both sides of the airport. The report did not specify whether it meant the international airport or the adjacent military airfield.

Several neighborhoods feel empty, even for a weekend day of Friday during the Muslim fasting month of Ramadan. Pickup trucks piled high with mattresses, washing machines and bags of clothing plied a highway north of the city as more families fled, either for safer villages or the Turkish border, 40 kilometers (24 miles) away. In most places, few shops are open. Just one barber shop was open for business on one main street; the rest of the block's stores had their metal shutters down.

"Those who are still here are those with no money to pay their way out and little food to take with them," said Mahmoud Bakkour, who sat with a dozen other rebels at a plastic table under a highway overpass in the Shaar neighborhood. "They have put their trust in God."

Bakkour boasted that rebel control was solid, putting the fight in the Islamic terms common among Aleppo's fighters.

"We are fighting the world with the words, 'There is no god but God,'" he said, citing the Muslim declaration of faith.

Under his breath, another fighter added, "We have very little ammunition."

Bakkour's men face few direct challenges on the ground, but can do nothing to protect the area from government air and artillery strikes.

The day before, an artillery shell exploded, spraying crowds of people waiting in line at the Qadi Askar bakery with shrapnel. Some 35 were killed and more than 50 were wounded, medics said.

Nevertheless, customers were back Friday, forming lines more than 100 meters (yards) long at each of the bakery's windows. Hussein Araj, 34, said he'd been waiting with his two daughters, aged 6 and 9, for more than an hour. Like many others, he'd come from other neighborhoods because his local bakery had closed, lacking supplies.

Many of those killed and wounded in the area end up at Dar al-Shifa, a private clinic now operating as a rebel field hospital.

A pickup screeched to the hospital's door and a fighter rushed in Friday, pressing his palm to his forehead to stop a wound from bleeding. Rebels carried in another man whose groin was soaked red with blood, his clothing torn and hands splayed out on the back of a wooden wagon.

The hospital had received more than 50 dead and 100 wounded the day before — the numbers higher than usual in part because of the bakery blast — said Younes, a doctor who gave only his first name, fearing for his safety.

Friday looked like it was going to be a "normal" day, he said, which would mean about eight dead and a few dozen injured.

One patient, 50-year-old Jamal Mahmoud, came in after shrapnel from a government shell tore a walnut-sized chunk from his arm. He said he'd always lived in the city and wouldn't flee.

"The regime needs to leave, not us," he said.

On the sidewalk across the street, a man wept over four bodies wrapped in striped blankets. They held the mother and her three boys killed in the same airstrike that killed the newlyweds. Their father's body would arrive shortly after.

Aleppo carries major symbolic and strategic value. It is the main hub of northern Syria and close to the northern countryside where rebels organize and bring in supplies from Turkey. Rebels have sought to control the city's center, which would further undermine government claims that its professional army can easily quash rebel forces.

"Those who think that the Syrian Arab army will be defeated are dreaming," Syrian Foreign Minister Walid Moallem told state TV on Thursday.

Along with Aleppo, the regime has been struggling to put down rebels in the capital, Damascus. In July, regime forces crushed a major attempt by rebels to take control of several parts of Damascus. But even after declaring victory, the government has faced frequent clashes there.

On Friday, government forces heavily shelled several western districts of the capital and clashed with opposition fighters. Damascus-based activist Moaz al-Shami described the shelling as "nonstop" and said gunners were firing from the Qassioun mountains overlooking the city.

The Britain-based Syrian Observatory for Human Rights said at least 74 people were killed nationwide Friday, 19 of them in Aleppo province.

The United Nations announced that Lakhdar Brahimi, a former Algerian foreign minister and veteran U.N. diplomat, would serve as the world body's new peace envoy. Brahimi, who was previously a U.N. envoy to Iraq and Afghanistan amid those countries' wars, will resume efforts to find a diplomatic solution to what has become an intractable civil war. U.N. Secretary-General Kofi Annan is leaving as envoy at the end of August after months of negotiations failed to bring about a cease-fire.

Activists estimate more than 20,000 have died in the conflict since March 2011.

The announcement came just as U.N. observers in Syria were beginning to pack Friday, preparing to close down their mission. The team — whose deployment was one of the only steps taken under Annan's peace plan — was supposed to watch over a cease-fire that never took hold. Instead, the observers were left trying to chronicle some of the more egregious instances of bloodshed.


Associated Press writer Ron DePasquale contributed from the United Nations.