A recently broadcast video clip shows terrorists moving through tunnels in the Gaza Strip to carry out attacks on IDF forces and to infiltrate Israel.

The video was recently broadcast on Al-Jazeera TV in Qatar and Al-Quds TV in Lebanon, according to The Middle East Media Research Institute, which provided an English-subtitled version of the clip on Monday.

In the footage, a reporter is given access to some of the tunnels that have been dug by the Izz ad-Din al-Qassam Brigades beneath Gaza.

Hamas terrorists have penetrated into Israel through at least five such tunnels in recent days, sparking deadly clashes with Israeli troops on the Israeli side of the border. Israeli military officials say Hamas sought to attack kibbutzim and moshavim in the area, and that some of the tunnels run directly beneath homes and residential areas. Prime Minister Benjamin Netanyahu said Sunday that such attacks could have had “catastrophic” consequences for Israel.

In the footage, heavily armed masked men in camouflage fatigue can been seen making their way through the narrow tunnels, some of which run for hundreds of meters. The narrator claims that the men are on their way to carry out a “military operation against the occupation forces.” The video shows apparently staged footage of fighters surfacing from the tunnels.

Six IDF soldiers have been killed by Hamas gunmen surfacing from such tunnels during Operation Protective Edge. Some 20 terrorists were killed by IDF forces shortly after emerging from the tunnels during the incidents.

The footage shows that the tunnels are well constructed with concrete slabs to support the walls and ceilings of the passageways, which have electric wiring and in some cases lighting. Computer-generated segments of the short movie also show rockets being fired at Israel from portals in the tunnels.

A member of the al-Qassam Brigades claims in the video that the tunnels take a few months to dig and that “dozens” of burrowers work shifts to complete the work. The man, whose identity is not given and whose features are hidden, says that al-Qassam brigades moved from bomb attacks, which were directed by Hamas chief bomb-maker Yahya Ayyash, to tunnel operations instead. Ayyash was assassinated by the Israeli Shin Bet security service with an exploding cellphone in 1996.

When Israel still controlled the Gaza Strip the tunnels were used to attack settlements and Israeli forces, the man explains, and says that the tunnels were the “straw that broke the camel’s back” forcing Israel to withdraw from Gaza in 2005. Now the tunnels are used to infiltrate Israel, he notes, and adds that the attacks will continue as long there are still prisoners held by Israel and the “land is still occupied.”