CAIRO: At least 85 people were killed and 80 more wounded when suspected militants targeted a mosque in Egypt's north Sinai with a bomb and gunfire, MENA state news agency said on Friday, citing an official source.

At least 75 more people were wounded in the attack that targeted worshippers during weekly Friday prayers, the report said.

The government declared three days of mourning after the attack on the mosque. 

Daesh's Egypt branch has killed hundreds of policemen and soldiers, and also civilians accused of working with the authorities, in attacks in the north of the Sinai peninsula.

Friday's attack took place roughly 40 kilometres west of the provincial capital of El-Arish during weekly prayers, police officials said.

The officials said a bomb went off at the mosque during prayers then gunmen opened fire.

The victims included civilians and conscripts praying at the mosque.