Cairo – Three Egyptian riot policemen were killed Tuesday in a rocket attack on their convoy in the Sinai Peninsula, where authorities are fighting a jihadist insurgency, the interior ministry said.

There was no immediate claim of responsibility for the attack which took place in North Sinai, a stronghold of the Egyptian branch of the jihadist Islamic State group.

A ministry statement said “unknown” assailants fired a rocket-propelled grenade at the police patrol on the road to the town of Sheikh Zuweid.

One vehicle was struck and three riot policemen killed, while eight others were wounded, the statement added.

Since Egypt’s military overthrew Islamist president Mohamed Morsi in 2013, jihadists have stepped up attacks on the army and police with near daily attacks carried out in North Sinai.

Most of the Sinai attacks are claimed by “Sinai Province”, the Egyptian branch of ISIS.