The Israel Defense Forces claims to have discovered “the biggest Hamas tunnel” in Gaza, spanning a length of four kilometers (about 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 (over 160 feet) underground and is equipped with electricity, ventilation and communication systems. It does not cross into Israel but ends 400 meters before the now-closed Erez crossing on the northern Israel-Gaza border, according to the IDF. The tunnel is part of Hamas’ “strategic infrastructure” and would be destroyed, the IDF said. In a video shared by the IDF, the Israeli military claimed the tunnel was created for Hamas troop movements and as a launching point for attacks. Footage shared by the IDF and allegedly filmed by Hamas to show the construction of the tunnel shows a large vehicle driving into the tunnel and a makeshift railroad inside it. CNN could not independently verify the footage or the IDF’s claims. 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. What to know about Gaza's tunnels: The myriad tunnels under Gaza are best known as passageways used to smuggle goods from Egypt and launch attacks into Israel. Colloquially referred to as the “Gaza metro,” the vast labyrinth of tunnels is also used to transport people and goods, to store rockets and ammunition caches, and house Hamas command and control centers — all away from the prying eyes of the IDF’s aircraft and surveillance drones. Hamas in 2021 claimed to have built 500 kilometers (311 miles) worth of tunnels under Gaza, though it is unclear if that figure was accurate or posturing. If true, Hamas’ underground tunnels would be a little less than half the length of the New York City subway system. During its offensive in the territory, the IDF claims it has exposed “hundreds of terror tunnel shafts throughout the Gaza Strip,” and says it is operating “to locate and destroy dozens of attack tunnel routes.” Recently, it has tested methods for flooding the Hamas tunnels. Pope Francis on Sunday addressed the deaths of a mother and daughter who were sheltering inside the Holy Family Parish in Gaza, where church leaders say they were killed by an Israel Defense Forces sniper. The Latin Patriarchate of Jerusalem — which oversees Catholic churches across Cyprus, Jordan, Israel, Gaza and the Palestinian territories — made the claim in a statement Saturday. CNN reached out to the IDF for comment when news of the deaths were first announced, and on Sunday renewed the request for comment. The majority of Christian families inside Gaza have taken refuge inside the parish since the start of the war, the Latin Patriarchate of Jerusalem said, adding that IDF tanks have also targeted the Convent of the Sisters of Mother Theresa, which houses 54 disabled people and is part of the church’s compound. “Some are saying, ‘This is terrorism and war.’ Yes, it is war; it is terrorism. That is why Scripture says that ‘God puts an end to war … the bow he breaks and the spear he snaps.’ Let us pray to the Lord for peace,” Francis said.