The explosives, mostly TNT that officials believe was recovered from land mines, were stashed in 34 plastic sacks, the security officer said speaking on condition of anonymity, because he is not authorized to give statements to the media. The explosives were to be smuggled to the Gaza Strip, he said.
Bedouin trackers working for the authorities led security forces to the underground hiding place in Nagaa Shabanah, a village a few kilometers south of the Rafah crossing between Egypt and the Gaza Strip.
The discovery came as hundreds of state-security forces and military intelligence personnel conducted a search operation in the Sinai Peninsula for two Palestinians believed to be plotting suicide attacks on Egyptian tourist resorts, the security officer said.
Smuggling across the border into Gaza or Israel has long provided a livelihood for some Bedouin. Weapons, cigarettes and foreigners seeking jobs in Israel are all taken surreptitiously across the border.
Israel has repeatedly accused Egypt of not doing enough to stop smuggling of weapons into Gaza, particularly through tunnels. Egypt recently said it would make a greater effort to stop smuggling.