Law, Power, and Justice

Israeli officials and soldiers who have since been in the tunnels — as well as current and former American officials with experience in the region — say the scope, depth and quality of the tunnels built by Hamas have astonished them. Even some of the machinery that Hamas used to build the tunnels, observed in captured videos, has surprised the Israeli military.

The Israeli military now believes there are far more tunnels under Gaza.

In December, the network was assessed to be an estimated 250 miles. Senior Israeli defense officials, who spoke on the condition of anonymity to discuss intelligence matters, are currently estimating the network is between 350 and 450 miles — extraordinary figures for a territory that at its longest point is only 25 miles. Two of the officials also assessed there are close to 5,700 separate shafts leading down to the tunnels.

In a meeting in January 2023, a top Israeli military official said the tunnels would not even be a factor in any future war with Hamas because of Israel’s military strength, according to a transcript of the discussion reviewed by The New York Times.

“Hamas has used the time and resources over the last 15 years to turn Gaza into a fortress,” said Aaron Greenstone, a former C.I.A. officer who has worked extensively in the Middle East.

Hamas released a video in November showing how it lured a group of five Israeli soldiers to a tunnel entrance in Beit Hanoun and then used a roadside bomb to kill the soldiers.

Ms. Richemond-Barak said Hamas had imported the tactic from Syrian rebels who killed dozens of government troops in a tunnel attack in 2014 in Aleppo.

Hamas has improved its ability to conceal the tunnels, but the senior official said the Israeli military had figured out one of the group’s operating models. The official called it the “triangle.” Whenever the Israeli military finds a school, a hospital or a mosque, soldiers know they can expect to locate an underground tunnel system beneath them, the official said.

Destroying the tunnels is not an easy task, the official said. They need to be mapped, checked for hostages and not just damaged but made irreparable. Recent attempts to demolish the tunnels by flooding them with seawater have failed.

The official estimated it could take years to disable the tunnel system.