At least four extremists were killed and 36 others arrested on Saturday in a security raid on their hideouts in major cities in Egypt's North Sinai province, a security source told Xinhua.
"The police-military raid in Arish, Rafah and Sheikh Zuweid also resulted in busting a weapon warehouse that has two machine guns, two sniper guns, two Kalashinkov rifles and various ammunition," the source added, noting that Tawfik Abou Mleih, a leading extremist Islamist, was among those arrested.
The security raid also defused an explosive device targeting military vehicles in southern Arish, while in Rafah it destroyed eight smuggling tunnels, 22 huts, three warehouses, four houses and one vehicle belonging to extremists.
Military spokesman Colonel Ahmed Ali said in a statement that 20 kg of heroine was also seized in the raid which is part of a massive security campaign in the Sinai Peninsula where terrorist attacks escalated following the ouster of Islamist President Mohamed Morsi in July last year.
Two extremists were killed in another raid on Friday evening in the restive peninsula, whereas extremists shot dead a soldier a day earlier.
On Wednesday, an extremist Islamist group, Ajnad Misr (Soldiers of Egypt), launched a series of blasts outside Cairo University, leaving at least one policeman killed and several others injured.
Since Morsi's removal, extremist groups have been launching terrorist attacks against security personnel and facilities in the Sinai Peninsula, the capital Cairo and some other provinces, leaving dozens killed and hundreds injured. Meanwhile the security forces have been waging a massive crackdown on Morsi's loyalists.
Last August the security used excessive force to disband two major pro-Morsi sit-ins in Cairo and Giza, killing about 1,000 people and arrested thousands.