Unknown assailants shot dead four policemen on duty in Egypt’s Qalyoubiya governorate on Sunday, a security source told state news agency MENA.

According to the source, a citizen was also killed when masked assailants opened fire on the policemen, who were raiding a hideout of drug traffickers north of Cairo. 

Police are currently sweeping the area to catch the assailants and are investigating the incident.

Security forces have often been targeted by militants since the ouster of Islamist president Mohamed Morsi in 2013, though most of the attacks have taken place in the troubled North Sinai governorate.