A bomb has exploded during Friday prayers at a mosque in Egypt's North Sinai province, killing at least 85 and injuring 80.

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Three Egyptian security officials told Associated Press that militants are behind the attack. They said extremists opened fire from four off-road vehicles on the al-Rawdah mosque in the town of Bir al-Abd, 40 km (25 miles) from the provincial capital of el-Arish.

At least 85 people have been killed and some 80 have been wounded, a spokesperson for the health ministry told Egyptian TV.

The explosion comes just weeks after a major militant attack against Egyptian Soldiers in the Sinai.

More than 50 soldiers were killed during a shootout with militants on 20 October.

Egypt has been fighting an Islamist insurgency since President Mohammed Morsi was ousted in 2013.

More to follow.

This is a breaking news story and will be updated regularly as new information and developments become available.