Militants attacked a checkpoint and killed eight security personnel on Wednesday in north Sinai where Egyptian forces have long been battling Islamists, state media said.
Five militants also died, state TV and state news agency MENA reported, with some on the run.
Egypt's military and police launched a major security campaign against Islamic State or related jihadist groups in the Sinai peninsula in February last year.
The campaign followed a jihadist attack in November 2017 on a mosque in which hundreds of worshippers died.
The military says hundreds of militants have been killed since it launched its campaign.
Earlier on Wednesday, state media said that a number of security checkpoints in the area had been attacked.