Egypt says security forces have killed 16 militants in two raids in the city of el-Arish in the Sinai peninsula.
The interior ministry said the jihadists were planning a series of attacks against vital installations and key figures in the area.
Police seized weapons, ammunition and explosive belts in the second hideout.
The army and police operation to eliminate an Islamist insurgency in Sinai began in February last year.
On Monday, three police officers were killed by a suicide bomber in the capital, Cairo.