Israel has returned the bodies of six gunmen, involved in the killing of 16 Egyptian troops during a raid on both sides of the border, to its Arab neighbour, Israeli military sources told AFP on Tuesday. The six were sent back overnight Monday, they said. The Israeli army said in a statement that the Kerem Shalom border crossing between Israel, Egypt and Gaza, which the attackers breached in Sunday's raid, was reopened on Tuesday morning. In Sunday's attack, 35 gunmen in Bedouin clothing opened fire on Egyptian troops before crossing into the Jewish state in an armoured vehicle, Egyptian officials said. Israel said five gunmen were killed on its side, adding that the armoured vehicle was destroyed by helicopter fire. Israeli media said that the remains of a sixth man was recovered from an explosive-laden pickup truck which blew up as it tried to negotiate barriers at the border crossing. The Egyptian army vowed on Monday to "avenge" the killings. Egypt also closed until further notice its Rafah crossing with the Gaza Strip, the only crossing to and from the territory not controlled by Israel.