At least 13 Egyptian policemen have been killed in the Sinai Peninsula after an armed group fired a mortar at a security checkpoint in the city of Arish, security and medical sources said.
The Islamic State of Iraq and the Levant (ISIL, also known as ISIS) claimed responsibility for Saturday's attack on several websites, with later confirmation from Egyptian state media.
Ambulances were subjected to heavy gunfire as they attempted to reach the wounded, the security and medical sources said.
Witnesses reported hearing a massive explosion and said the city's entrances and exits had been closed off by security forces.
Security sources said government forces were later able to kill five of the fighters who carried out the attack.
Egypt is battling an armed campaign that gained pace after its military overthrew President Mohamed Morsi.
The campaign, mounted by ISIL's Egyptian branch in Sinai Province, has killed hundreds of soldiers and police and has also targeted Western interests within the country.
ISIL controls large parts of Iraq and Syria and has a presence in Libya, which borders Egypt.