Hamas is digging tunnels next to United Nations facilities under the assumption that the IDF will not target them during a future conflict, defense officials warned on Sunday. The officials said a tunnel Hamas had been digging adjacent to a UN school in Beit Hanun had collapsed earlier this month. According to some reports obtained by Israel, the collapse of the tunnel caused damage inside the school. UNRWA spokesman Chris Gunness denied claims that a tunnel was being dug under a UN school, and said, regarding claims tunnels were being dug adjacent to UN schools: "It is not within the UN mandate to police what is happening under the streets of Gaza." According to one official, the tunnel was being dug directly next to the school and likely underneath it as well. The IDF's concern, a defense official said, was that Hamas was digging tunnels adjacent to UN and other international facilities because the terror group knew that the IDF would think twice before bombing them. The official said it was certain that the digging was being done without the UN's knowledge. The idea of tunneling near the UN school, the official said, was a lesson Hamas had learned from Operation Cast Lead earlier this year, during which the IDF did its utmost to avoid targeting UN facilities. "Hamas uses civilian infrastructure to hide behind," explained the official. "This is another example of Hamas's cynical use of a school." This is not the first time Palestinian terrorists have used the Beit Hanun school. In October 2007, an IAF drone videotaped three terrorists preparing and then launching mortars from within the UN school compound in Beit Hanun.