Egyptian border guards have discovered a tunnel, 2.8 kilometres long and three meters deep, Military Spokesman Mohamed Samir said.
The tunnel was used by "terrorists" and "criminals" in the smuggling of individuals, goods, and "arms and ammunition", Samir said in a statement on his official Facebook page.
Egypt is building a "buffer zone" at the shared border area between North Sinai and the Gaza strip. The cabinet issued a decision last October to clear 500 metres of the border area of civilians.
The area was, however, doubled to 1,000 meters in November, after discovering some tunnels in the Peninsula over 800 metres long.
And Egyptian authorities are considering tightening up the penalties for building these tunnels - with life imprisonment:
Egypt's cabinet approved on Wednesday a draft legislation proposed by the president punishing those who dig or use border tunnels for communication with foreign countries by life in prison.
The draft law amends article 82 in the penal code, adding that the life-in-prison penalty would punish whoever "digs, prepares or uses a road, a passage or an underground tunnel at border areas to communicate with a foreign body, a state or one of its subjects" or to help persons, goods, equipment or machines in and out of the country, according to a statement by the cabinet.
The same penalty applies to those who are aware of the use (or planned use) of underground tunnels for the aforementioned purposes without informing the concerned authorities, the legislation adds.
The legislation also allows the government to seize any buildings beneath which tunnels are dug or tools used to dig them.