"Over the past six months, border guards managed to destroy 521 entry points into underground tunnels," army spokesman Mohamed Samir told Al Ahram newspaper in an interview published on Monday.
The Egyptian army says it destroyed 521 tunnels linking the Sinai Peninsula with the Palestinian lands located along the border with the blockaded Gaza Strip.
Some of the tunnels, the official said, extended over 2.8 kilometres from the border into Egypt.
He added that some of the unearthed tunnels were even equipped with railroad tracks, lighting, ventilation and radio transmitters.
Egyptian authorities announced on Sunday that the Rafah border will be open for two days starting from Tuesday. Travel will be allowed in one direction only, from the Egyptian side to the Palestinian.
The Rafah border crossing is the main road linking the Egyptian border town of Rafah to the Palestinian Gaza strip. It has been mostly closed since the overthrow of deposed president Mohamed Morsi in 2013, as a result of subsequent attacks on security and military headquarters in the bordering Sinai Peninsula.