CAIRO: Egyptian security sources said at least three policemen and a soldier were injured close to the Sinai town of Sheikh Zuwaid on Saturday when armed attackers fired a rocket-propelled grenade at a convoy during recent military operations in the restless peninsula. Earlier this month, 16 soldiers were killed when militants attack a border outpost near Gaza and Israel. The attack has seen a massive military response by Cairo, which has included air strikes in the Sinai. Security said the Saturday attack took place when police were returning to the city of al-Arish after arresting two suspects in the border town of Rafah. “The forces were entrapped by extremists when they were returning from a raid in Rafah … one armored vehicle was targeted by a rocket,” a source told Reuters news agency.