A policeman was killed and another seriously wounded in northern Egypt on Monday when gunmen in a parked car fired at patrolling officers, a security official said.

A policeman was killed and another seriously wounded in northern Egypt on Monday when gunmen in a parked car fired at patrolling officers, a security official said.

The two policemen were on patrol in the Nile Delta province of Gharbiya when they approached a car parked at the side of a road, the official said.

The car's occupants then opened fire on the officers before escaping, he said.

Extremist groups have regularly launched attacks on police and soldiers since the overthrow of Muslim Brotherhood’s president Mohammad Mursi in July last year by former army chief Abdel Fattah al-Sisi, now president of Egypt.

Attacks initially centered on the desert peninsular of Sinai but have spread to the Nile Delta region and to Cairo.

The government puts deaths from such incidents at around 500, almost all of them police and soldiers.

Two extremists groups have claimed the most spectacular attacks of recent months: Al Qaeda-inspired Ansar Beit al-Maqdis (Partisans of Jerusalem), based in Sinai, and Cairo-focused Ajnad Misr (Soldiers of Egypt).