The Israel Defense Forces (IDF) on Sunday said it has uncovered “the biggest Hamas tunnel” in Gaza, spanning a length of four kilometres (2.5 miles).

The IDF said the tunnel, secured “a few weeks ago” but revealed to the public Sunday, is wide enough to drive a large vehicle through, reaches up to 50 meters underground and is equipped with electricity, ventilation and communication systems.

It does not cross into Israel but ends 400 meters before the now-shut Erez Crossing on the northern Israeli-Gazan border, according to the IDF. Erez was stormed during the October 7 attacks.

The tunnel was a part of Hamas’ “strategic infrastructure” and would be destroyed, according to the IDF. In a video shared by the IDF, the Israeli military claimed that the tunnel was created for Hamas troop movements and as a launching point for attacks.

In a statement Sunday, the IDF alleged that the tunnel system was a project of the brother of Hamas leader Yahya Sinwar, Muhammad Sinwar. The IDF did not provide any evidence to support the claim.

The IDF claims to have exposed “hundreds of terror tunnel shafts throughout the Gaza Strip” and says it is operating “to locate and destroy dozens of attack tunnel routes.”

Vast labyrinth

Hamas has claimed to have built 500 kilometers (311 miles) worth of tunnels under Gaza, though it is unclear if that figure was accurate.

The tunnels under Gaza are used to smuggle goods from Egypt, launch attacks into Israel, store rockets and ammunition caches and house Hamas command and control centers.

Some of those taken hostage in the October 7 attacks described being taken to them and being forced to march for hours.

Last month, the Israeli military uncovered a tunnel shaft on the grounds of the Al-Shifa hospital complex, the enclave’s largest medical facility. Its discovery has been central to the IDF’s argument that there may be a network of tunnels below the hospital.

The hospital, Gaza’s largest, was raided by Israeli forces last month, who accuse Hamas of running a command center beneath it. Hamas and hospital officials say it has only been used to treat patients.

If successful, flooding could be ramped up to degrade the tunnel network on a larger scale.