Combat inside tunnels is incredibly difficult, Luttwak said, noting that it requires a specific skill set and that standard tactics and weaponry are often not suitable inside a subterranean setting. “Tunnel warfare is not for amateurs,” he said.

Spencer noted that it’s difficult to execute offensive operations inside the tunnels because navigation and communication systems often don’t work so far underground, and even night-vision goggles struggle, as they require some ambient light.

The sound emitted by a weapon being fired is also amplified inside the tunnel, posing immense risk to the soldier firing the gun, requiring intensified hearing protection, he said.

Because the tunnels are so integral to Hamas’s operations, dismantling the network is equally integral to Israel’s stated goal of totally eradicating Hamas, Richemond-Barak said. But sending soldiers into the tunnels would be incredibly risky, and is “very much a last resort” for instances such as rescuing the hostages, she said, though even that scenario would require a complex weighing of various factors.

The precarious position of the tunnels beneath the bustling streets of Gaza — as well as the holding of hostages within the tunnels — has created an array of difficult decisions for the Israeli military, Richemond-Barak added. The only way to destroy the network is by airstrikes, she said, but the tunnels sit below areas densely populated by civilians.

Israel called for Palestinians in northern Gaza to evacuate to the south, amid airstrikes and ahead of a planned ground invasion. But some Palestinians said they would not evacuate, amid safety concerns following reports of a strike on a convoy of evacuees. The U.N. agency for Palestinian refugees said that many Palestinians, particularly pregnant women, children, the elderly and the disabled, would not be able to evacuate. Human Rights Watch said the Israeli order was “not an effective warning,” citing poor road conditions and dwindling fuel supplies.