Assailants have killed at least 18 Egyptian policemen in a bomb attack on a security convoy on the Sinai Peninsula.
The extremist group Islamic State (IS) has claimed responsibility for the attack on September .
Egyptian authorities said the assailants detonated an improvised explosive device and destroyed three armored vehicles and a signal-jamming vehicle in the incident.
A gunbattle erupted and the attackers shot at ambulance workers, injuring four, officials said.
IS claimed responsibility in a statement posted by its news agency Amaq.
The attack took place in the northern part of the Sinai Peninsula, which borders the Gaza Strip.
IS militants have killed hundreds of soldiers and police in the region since 2013, when the military ousted Islamist President Muhammad Morsi after mass protests against his rule.
Suicide car bombs blew up at two military checkpoints in North Sinai in July, killing at least 23 soldiers in one of the deadliest attacks on security forces in years.