Suspected Islamist militants have killed 12 soldiers and injured eight in an attack on an army checkpoint in the Sinai Peninsula, Egyptian security sources say.
The army says 15 militants were also killed in the attack, which took place near the town of Bir al-Abd.
Gunmen from the Sinai Province group are reported to be behind the attack.
It is Egypt's most active insurgent group, which pledged allegiance to so-called Islamic State in 2014.
Officials said a gun battle erupted after the militants opened fire on the checkpoint with light arms and heavy machine-guns.
Friday's attack was the latest in what appears to be a surge in the number of operations launched by the militants.
Sinai Province: Egypt's most dangerous insurgents
- Originally called Ansar Beit al-Maqdis (Supporters of Jerusalem), but changed its name after it pledged allegiance to so-called Islamic State in November 2014
- Began with rocket attacks on Israel but refocused on targeting Egyptian security forces after the removal of President Morsi
- Its aim is thought to be to take control of the Sinai peninsula to turn it into an Islamist province
- Deadliest attacks include killing of 33 security personnel in North Sinai in October 2014
- The number of active members is believed to be between 1,000 and 1,500
- Believed to have cells in Cairo, Giza and the Western Desert
However, the army has appeared to have had a degree of success in suppressing the militants recently, and it is some time since the fighters carried out an attack on the scale of this one.
Egypt has battled militants in Sinai for years, but Islamist militancy has risen since the army deposed President Mohammed Morsi of the Muslim Brotherhood in 2013.
In August, the Egyptian military said it had killed the leader of Sinai Province, along with dozens of its fighters.