Cairo: Egypt's security forces suffered one of their heaviest attacks after militants firing rockets and detonating explosives hit a police operation on Friday in the western desert, authorities and security sources said on Saturday.

Three security sources said at least 52 police officers and conscripts had been killed in gun battles that erupted in the remote desert, but Egyptian authorities said only 16 men had died when their patrol came under attack.

Egyptian authorities on Saturday said two police operations were moving in on a suspected militant hideout on Friday when one of the patrols came under fire from heavy weapons in a remote area 135km southwest of Cairo.

The interior ministry said 16 policemen were killed in that part of the operation, and 13 more were wounded. At least 15 militants were also killed in the gun fight. The statement did not give details on any casualties in the other police patrol.

"As soon as the first mission approached the location of the terrorist elements, they sensed the arrival of the forces and targeted them using heavy weapons from all directions," the interior ministry said. One security source said the convoy was attacked from higher ground by militants.