At least 54 Egyptian police officers have been killed in a raid on a suspected militant hideout near Cairo, according to security officials.
The officials, who requested anonymity, said the security forces apparently were ambushed Friday night by militants after they converged on the hideout in the western desert area of al-Bahriya.
One senior security source said a convoy of four SUVs and one interior ministry vehicle were targets of a surprise attack by militants firing rocket-propelled grenades and detonating explosive devices.
Twenty officers and 34 conscripts are among the fatalities, sources said. The Egyptian Interior Ministry said in a statement Saturday "a number of our men were martyred" but did not provide information about casualties.
No group has claimed responsibility for the killings, but local media reports said the militants are followers of the Hasm Movement, which Egyptian security forces claim are linked to the Muslim Brotherhood, an outlawed group that once led the country. The Brotherhood denied any link to the movement.
Friday's attacks are the latest in a series of deadly encounters suffered by Egypt's security forces this year as they confront a tenacious growing Islamic militancy.
Egypt has been struggling to counter uprisings by militants led by an affiliate of the Islamic State that is centered primarily in the northern region of the Sinai Peninsula. The country's efforts, however, have been stymied by a recent increase in the number of attacks on the country's mainland.
The ambush was one of the most deadly attacks on security forces since militants began targeting government forces after the 2013 ouster of Egypt's first freely elected President Mohamed Morsi, whose one-year rule was divisive.