Two senior Egyptian army officers were killed during a raid on a jihadist hideout north of Cairo on Wednesday, as security forces close in on militants in the Nile Delta.
Six members of the Al-Qaeda-inspired Ansar Beit al-Maqdis (Partisans of Jerusalem) group, which has been implicated in a spate of attacks on security forces, were also killed in the hours-long shootout, the army and police said.
The jihadists have increasingly shifted their campaign of bombings and shootings from their base in the restless Sinai Peninsula to the Nile Delta and the capital.
Ansar Beit al-Maqdis has claimed responsibility for some of the deadliest attacks in a wave of violence that has killed more than 200 soldiers and policemen since the army overthrew Islamist president Mohamed Morsi in July.
The brigadier and colonel killed in the early morning shootout were both bomb disposal experts, the army said.
The cell targeted was suspected of involvement in a Saturday attack on a military checkpoint that killed six soldiers, as well as a January bombing of Cairo police headquarters.
The interior ministry said several barrels filled with explosives were discovered in the warehouse near the Nile Delta town Al-Qanatir Al-Khayriya, 30 kilometres (20 miles) north of the capital.
Television footage showed forensic experts sifting through bomb-making materials, including ball bearings used to make blasts more deadly.
- 'All prepared to die' -
Police also found a vehicle previously identified as the getaway car used in the Cairo police headquarters bombing and last week's checkpoint attack.
Most of the attacks since Morsi's overthrow have taken place in the Sinai, where jihadist leaders are believed to be based.
The group has posed a persistent challenge to army chief Abdel Fattah al-Sisi, who is widely expected to contest and win upcoming presidential elections.
Sisi attended the funeral of the slain officers on Wednesday.
"By God, we are all prepared to die now for our country," he told relatives of one of the officers in footage broadcast on state television.
Ansar Beit al-Maqdis had claimed the downing of a military helicopter in the restive region using a heat-seeking missile, as well as the Cairo police headquarters bombing.
The group said last week that its founder, Tawfiq Mohamed Fareej, was killed recently when a car accident set off a bomb he was carrying.
Fareej was the field commander of an August 18, 2011 cross-border raid into Israel that killed eight Israelis, the group said.
Several new militant groups have sprung up in the face of a deadly security crackdown on Morsi's supporters, which has killed at least 1,400 people, according to Amnesty International.
Interim president Adly Mansour on Wednesday ordered the justice ministry to open an investigation into the August dispersal by security forces of the Rabaa al-Adaweya Islamist sit-in that left hundreds dead.
A new Islamist group, Ansar al-Shariah, claimed responsibility on Monday for a spate of attacks on police in the Nile Delta that it said had targeted 28 security men.
The same name is used by jihadist groups in several other countries.
The government has designated Morsi's Muslim Brotherhood a terrorist organisation, but the group says it is committed to peaceful protest.
On Wednesday, at least two people were killed when student supporters of Morsi clashed with police at several university campuses.
Morsi and dozens of Brotherhood leaders face trial on a number of charges, including collusion with militants to carry out attacks.
Former president Hosni Mubarak, toppled in a 2011 popular uprising, also faces trial on various charges.
On Wednesday, a court postponed his corruption trial to March 27.