Egypt said Monday it has dismantled three "terrorist cells" targeting security forces, including one run by jihadists and another operated by student supporters of ousted Islamist president Mohamed Morsi.
Militants have stepped up attacks on security forces since the army overthrew Morsi in July last year.
Such attacks, which officials say have killed some 500 people, are in retaliation for a deadly police crackdown on Morsi supporters.
"Police efforts resulted in the arrests of terrorist elements of these cells which targeted security forces," interim interior minister Mohamed Ibrahim said at a news conference.
He said one group was operated by Ajnad Misr (Soldiers of Egypt), a jihadist movement which has claimed several attacks targeting policemen in Cairo.
"Police arrested three leaders and four members of this group run by Ajnad Misr in Giza province" near Cairo, Ibrahim said.
"They confessed to killing members of the army and police in a series of bombings, including one that killed a police brigadier general near Cairo University" on April 2, he said.
That day Ajnad Misr said it was behind three bombings outside the university.
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"The security forces also discovered and dismantled two cells that planned to attack the army, police and public installations," Ibrahim said.
One was run by a student, Abdullah Hesham, who had fought in Syria with the Ahrar al-Sham rebel group battling President Bashar al-Assad's forces.
Ibrahim said Hesham had received funds from Muslim Brotherhood leaders in Qatar and had also taken part in a pro-Morsi sit-in at Cairo's Nahda Square last August.
Hundreds of Morsi backers were killed on August 14 when police stormed the Nahda and Rabaa al-Adawiya squares to disperse sit-ins demanding Morsi's reinstatement.
Ibrahim said police arrested Hesham and another student who planned to attack security forces and state installations.
He said the other group, financed by a Brotherhood leader, was also dismantled and three of its members arrested, adding that it planned to attack the state television headquarters and the Media Production City in Cairo, where many satellite television channels are based.
Reporters were also shown video footage of confessions by some detainees.
Since Morsi's ouster, most militant attacks have been in the restive Sinai Peninsula, but jihadists have also staged spectacular assaults farther afield in the Nile Delta and in Cairo.
The deadliest attacks have been claimed by Sinai-based Ansar Beit al-Maqdis, a jihadist organisation inspired by Al-Qaeda.