North Sinai Security Directorate forces arrested Egyptians and Palestinians in Arish over suspected involvement in an earlier attack on the city's civil defense building.
Four Egyptians and five Palestinians were arrested in the sweeping operation.
The suspects were arrested inside a mosque near the meteorological authority building, close to al-Nasr Mosque, a supposed haven for jihadi groups in Arish.
Authorities claimed the four Egyptians had been drafted to attack army and police troops in North Sinai.
The Sinai Peninsula has witnessed escalating attacks against army and police since the overthrow of former President Mohamed Morsy. Attacks are largely blamed on extremist groups in the region.
The army said Tuesday it detained 11 suspected terrorist elements, including two Palestinians.
Twenty-five Central Security Forces personnel were killed in an attack by unknown assailants early Monday, in the most violent assault on security in the peninsula since August 2012.
Edited translation from Al-Masry Al-Youm
