Syria's rebels were jubilant on Tuesday, claiming to have shot down a jet and captured its pilot, an apparent victory against the overwhelmingly superior firepower of President Bashar al-Assad's forces.
Video uploaded onto the Internet on Monday showed the jet bursting into flames as it streaked through the sky amid heavy gunfire. The rebels said they had hit it with newly acquired high-calibre anti-aircraft guns.
The government said it had crashed due to technical problems while on a "regular training mission".
Rebels also released a video of a man they said was the pilot. They said he had been captured after ejecting while his stricken aircraft plunged from the sky.
"We will treat this prisoner according to what is required of us by our religion, our morals and the protocols in the Geneva convention related to prisoners of war," a rebel identified as Captain Abu Laith said in the video.
However, other disturbing footage on YouTube appeared to show rebels meting out violent justice. In one video, dead bodies are thrown from the rooftop of a post office, while a crowd of shouting men watch. Enraged members of the crowd kick the bodies down stairs and can be heard calling them members of the shabbiha pro-government militia.
In another video, a young man's throat is slit with a knife by captors who accuse him of being a member of the shabbiha while his blood pours on the ground and his last breath rattles. Rebels said the video may have been made by government forces to discredit them.
Such images will cause alarm among Western countries that have backed the rebels publicly but are worried about the presence in their midst of hardcore al Qaeda-style Sunni Muslim fighters who use the ruthless tactics that became common in the sectarian bloodbath in neighbouring Iraq.
The shabbiha, mainly drawn from Assad's minority Alawite sect, have been accused of carrying out massacres of Sunnis.
The downing of a fighter jet would be a rare coup for the lightly armed rebels up against the superior weaponry of Assad's forces, which have made increasing use of air power in recent months.
The Pentagon said it deplored what it saw as Assad's increasing use of air power but stopped short of suggesting any move towards steps such as a no-fly zone.
Reuters journalists have seen fighter jets firing rockets at rebel-held villages and districts in the northern city of Aleppo, Syria's biggest city and this month's main battle front.
Bodies in street
Rebels have poured since the middle of July into the capital Damascus and then Aleppo, transforming the conflict after a bomb killed four members of Assad's inner circle. Government forces have largely recaptured Damascus, but fighting has raged on in Aleppo, worsening the plight of residents.
On Monday, four civilians lay dead in a street in Saif al-Dawla, next to the bitterly contested Salaheddine district. All were victims of army sniper fire, rebels said.
The bodies of a man and a woman were slumped in a bullet-riddled yellow taxi. A bloated male corpse lay on a pile of rubbish. Another dead man sprawled in the street, his face purple and bloated, with several dolls lying near his hand.
Food is running short in the city of several million, and what is left has become far more expensive. State-run groceries that sold heavily subsidised staples have shut. In the Bustan al-Qasr district, hundreds of men lined up for bread.
At a makeshift hospital set up to treat wounded, one doctor said some people were arriving seeking food rather than medicine.
Another doctor described a man who had been shot in the foot while carrying home food for his family. He was more worried about losing his groceries than about his wound.
"He started crying: 'My food! My food! Someone catch my tomatoes!'" said the doctor who witnessed the incident.
UN humanitarian chief Valerie Amos will go to Syria on Tuesday to discuss how to increase emergency aid, but diplomats said fighting must ease to allow access to trouble spots.
"Two million people are now estimated to have been affected by the crisis and over one million have been internally displaced," a U.N. statement said.
The head of a faltering UN monitoring mission said violence was intensifying across Syria and accused both sides of ignoring the plight of civilians caught up in the conflict.
"The indiscriminate use of heavy weapons by the government and targeted attacks by the opposition in urban centres are inflicting a heavy toll on innocent civilians," General Babacar Gaye said in Damascus. "I deeply regret that none of the parties has prioritised the needs of civilians."
Syria has been isolated in the region as its Arab League neighbours and Turkey have taken up the anti-Assad cause, leaving him with few allies, including Russia, China and Iran.
Foreign ministers at a meeting of the 57-member Organisation of Islamic Cooperation in Jeddah, Saudi Arabia, agreed on Monday to suspend Syria's membership, an OIC source told Reuters. The motion, which requires a two-thirds majority and is opposed by Tehran, will be adopted during a two-day summit in Mecca.
China said it would host Assad aide Bouthaina Shaaban on Tuesday and consider separately inviting opposition figures. The opposition has rejected Chinese peace overtures.