Security forces in North Sinai have arrested 21 suspected militants and destroyed eight tunnels connecting the border town of Rafah with the Palestinian Gaza Strip, the Egyptian army's spokesman Ahmed Ali said on Wednesday.

Ali said that four of the 21 detainees were jihadi militants tasked with monitoring the army's movements in the town of Sheikh Zuweid in preparations for an attack on security forces.

One person arrested in the campaign had broken out of jail during the January 2011 uprising where he had been serving a sentence of 85 years for a variety of charges, Ali said.

The rest of the suspects will undergo security screenings, he added.

The army's two-day offensive in North Sinai also hit a number of militant hideouts, said Ali, including two warehouses containing explosives and weapons along with a number of vehicles and motorcycles.

Egypt's army has been locked in an ongoing battle with suspected Islamist militants since the ouster of Islamist president Mohamed Morsi in July, as militant groups have stepped up attacks against security forces.

While the attacks have remained largely in the Sinai Peninsula, militants have also claimed responsibility for bombings and killings in the Nile Delta and Cairo.