The two groups planned attacks during the Muslim festival of al-fitr, which begins in Egypt on Sunday, according to a statement from the Interior Ministry.
Weapons and bomb belts were found at the hiding places.
Police struck on Saturday. Firearms erupted and two police officers were injured.
In early May, a similar raid was made in Bir al-Abd in northern Sinai. Then 18 suspected Islamists were killed.
The security forces have long sought to defeat the jihadist uprising in northern Sinai, which has escalated since President Mohammad Mursi, of the Muslim Brotherhood, was deposed in 2013.
Crowds of police, military and suspected jihadists have since been killed and in February 2018 Egypt launched a major offensive to quell the uprising.