A doctor at a Libyan hospital says more than 50 rebels have been killed in six days of fighting with government forces over the strategic eastern oil town of Brega.

The new toll comes after Mohammed Idris, a doctor at the Ajdabiya hospital where the casualties were taken, raised the number killed in Tuesday's fighting to 27, with 83 wounded. Idris said Wednesday that most had been shot in the head and chest.

An uprising against the rule of Moammar Gadhafi in February has left much of Libya's east in rebel hands. The fight, however, has been stalemated outside the gates of the heavily defended Brega.

Libya's government spokesman has put the rebel death toll closer to 500.