At least 25 Egyptian security personnel have been killed in an explosion at a checkpoint in the Sinai peninsula
Initial reports from security sources suggested the blast, which targeted two armoured vehicles, was caused by a car bomb.
But one Sinai official said the cause was a rocket-propelled grenade.
The explosion happened at the Al Kharubbah checkpoint, around 50 kilometres from the border with the Gaza Strip.
Security sources said that the large explosion and high death toll were likely due to the armoured vehicles being loaded with ammunition and weapons.
Medical sources said the death toll was likely to increase because some of the wounded were in critical condition.
There has been no claim of responsibility for the attack.