Rebels in eastern Libya say their forces have been mistakenly hit in a Nato air raid.
Doctors in Ajdabiya told the BBC 13 rebel fighters had been killed by the strike on a rebel tank position.
The BBC’s Wyre Davies reports chaotic scenes on the outskirts of Ajdabiya, with rebel forces in retreat reporting being hit by Nato air strikes.
Rebel forces in the area began retreating on Wednesday after heavy bombardment from government forces.
Our correspondent saw dozens of flat-bed trucks taking heavily armoured vehicles and rocket launchers from the rebel side towards to the town of Brega.
Ambulances were heading in the opposite direction, towards the hospital Ajdabiya, following the apparent Nato hit.
One rebel commander told the BBC he saw at least four missiles land among rebel fighters.
Many people have been killed and many more have been injured, he said.