The rebel leadership described the deaths as an unfortunate mistake and called for continued air strikes against Qaddafi's forces, which thrust east out of Brega on Saturday using rockets and machineguns. Their rapid advance sent hundreds of anti-government fighters fleeing back down the coast road, erasing two days of rebel gains. Better-trained and experienced rebel fighters had earlier been fighting Qaddafi's forces inside Brega, but it was unclear whether they had held their ground or pulled back into the desert. Most journalists moved back east with the rebels. Before the rebels fled east, a Reuters correspondent saw at least four burnt-out vehicles including an ambulance by the side of the road near the entrance to Brega. Men prayed at freshly dug graves covered by the rebel red, black and green flag nearby. "Some of Qaddafi's forces sneaked in among the rebels and fired anti-aircraft guns in the air," said rebel fighter Mustafa Ali Omar. "After that the NATO forces came and bombed them." Rebel fighters at the scene said as many as 14 people may have died in the bombing, which was happened around 10 p.m. local time (2000 GMT) Most blamed a Gaddafi agent for deliberately drawing the friendly fire but some said other rebels had shot into the air by accident. "The rebels shot up in the air and the alliance came and bombed them. We are the ones who made the mistake," said one fighter who did not give his name. Rebel spokesman Mustafa Gheriani said: "You have to look at the big picture, mistakes will happen that we are trying to get rid of Gaddafi and there will be casualties, although of course it does not make us happy". He said the rebel leadership still backed air strikes to protect Libyan civilians. "We are pleased to see the NATO forces doing what they are assigned to do protecting civilians, enforcing a ceasefire and creating a situation to allow peaceful protests," Gheriani told Reuters in the rebel eastern stronghold of Benghazi.