Rebel forces in eastern Libya allege that thirteen of their soldiers were accidentally killed by at least four missiles fired during a NATO air strike.

The BBC reports that the deaths occurred near Ajdabiya, where there are chaotic scenes of rebel fighters fleeing NATO air raids. On Wednesday, the rebels retreated to escape heavy attacks from their real enemy, Libyan government forces.

Several rebel tanks were also destroyed.

A correspondent for BBC “saw dozens of flat-bed trucks taking heavily armored vehicles and rocket launchers from the rebel side towards to the town of [oil port] Brega. Ambulances were heading in the opposite direction, towards the hospital [in] Ajdabiya, following the apparent NATO hit.”

An official of NATO in Brussels said it would look into the matter.

The tragic killings come one day after rebel chiefs complained that NATO air strikes were not doing enough to stop forces loyal to Moammar Gaddafi.