Two policemen were killed and a third was injured on Monday in a series of attacks targeting Egyptian security personnel, a security source said. Police Sergeant Hassan Sayed was shot in the head by unidentified militants driving a motorbike in the central Beni Sueif province, killing him instantly, the source said, Haberler.com reported. A low-ranking policeman was also killed by a shot to the head outside a government headquarters in the Nile Delta city of Mansoura, the source said, adding that the two attackers had both managed to flee the scene. Two armed gunmen on a motorbike also shot and injured a non-commissioned police officer in the town of Al-Saff in the Giza province adjacent to Cairo. He was brought to hospital in critical condition after sustaining wounds to the face, the source said. No group has claimed responsibility for Monday's shootings, the latest in a series of attacks on security personnel that have remained ongoing since the army ousted elected president Mohamed Mursi last July.