Egyptian security officials say a senior army officer was killed and another was injured when a cross-border smuggling tunnel with the Gaza Strip collapsed after troops went into it to investigate.

The officials say the tunnel was discovered on Friday in the Egyptian town of Rafah in northern Sinai. One of its entrances was close to the town's intelligence headquarters while the other was apparently on Gaza's side of the border, in the Palestinian town of Rafah.

The officials say Lt. Col. Hussam Hamdi Abdel-Aziz was killed in the cave-in and Maj. Ahmed Farouq Mostapha was injured. The officials spoke on condition of anonymity according to regulations.

Egypt has been trying to clear a buffer zone with Gaza in order to stamp out a cross-border tunnel network operated by Hamas.