THE only way Israel can destroy Hamas' underground army will be to bombard them in a bloody attack, an intelligence expert has warned.
Israeli forces may have to pummel their 311-mile maze of tunnels with airstrikes before storming in all guns blazing, and it will cost them.
Dr Matthew Levitt, a counter terror expert from The Washington Institute think tank, said that the result will be brutal, but it must be done.
He told The Sun that the "most significant" challenge the IDF faces is Hamas' network of underground passages, which is feared to be used to hide terrified hostages.
While Dr Levitt - who has seen several of the tunnels firsthand - thinks it is possible to destroy Hamas' underground terror army, he warned it "will come with a severe cost" for Israel.
Military experts have also warned that a daunting underground mission against heavily armed Hamas terrorists could cost hundreds of Israeli lives.
Dr Levitt explained that the tunnels provide Hamas the chance to carry out "sophisticated ambushes" of the IDF, and that Israel needs to attack key parts from the air before storming in on the ground.
The expert said that such ambushes could give Hamas "wounded soldiers, more individuals and corpses" to negotiate over.
"It is a series of intricate tunnels, not small tunnels. You can even go online and see videos of militants driving motorcycles through them," he said.
"With multiple turnoffs, different places that are intended to be able to move people and weaponry, store weaponry, outside of the view of Israeli overhead surveillance.
The tunnels are not impossible to destroy, he said, although the attempt will incur losses.
"It's not something that can't be overcome. It helps explain a lot of the aerial bombardment that you've seen over the past 2 weeks.
"The Israelis are trying to take out as much munitions, certain types of munitions, but also key parts of the tunnel as possible."
Dr Levitt described a tunnel that he visited, dug from Gaza into Egypt with a U-turn into Israel.
He dubbed it sophisticated and expensive, with "steel, reinforced doors".
The network of tunnels has been expanding since Hamas took control of the Gaza Strip in 2007, and thousands of terrorists are thought to have fled there after attacking Israel on October 7.
Israel's military retaliated with a barrage of airstrikes - but will need to unleash an all-out ground assault to reach terrorists hidden in the network.
An Israeli grandmother released by Hamas on Monday shared the "hell" she went through while imprisoned in the "spider web"; of tunnels.
Yocheved Lifshitz, 85, held on for two weeks at the hands of Hamas terrorists who kept her underground.
The traumatised woman said she was forced to walk kilometres through the maze of passages after being dragged into Gaza.
Jonathan Conricus, an Israel Defence Forces (IDF) spokesman, said: "Think of the Gaza Strip as one layer for civilians and then another layer for Hamas.
"We are trying to get to that second layer that Hamas has built.
"These aren't bunkers for Gazan civilians. It's only for Hamas and other terrorists so that they can continue to fire rockets at Israel, to plan operations, to launch terrorists into Israel."
The terror group began building its defensive tunnels - dubbed "Gaza Metro" - almost two decades ago in a bid to dodge Israeli rocket attacks.
Hidden up to 100ft below the surface, the entrances are enclosed under the floors of homes, mosques and schools - allowing fighters to move unseen between homes and alleyways within Gaza.
It is used by the warped group to transport people and goods as well as store rocks and ammunition.
The tunnels are understood to be connected to launch pits where rockets have been fired from towards Israeli areas.
Hamas' command and control centres are also housed in the intricate system away from Israel's watch.
And it's understood the entire network is heavily laden with booby traps and homemade bombs.
Each tunnel is reinforced with concrete and some are so narrow fighters are unable to stand up in them.
Others, however, are much more spacious - allowing terrorists to run through them and transport weapons and contraband.
The exact size of the network is unclear - but in 2021 Hamas claimed to have dug out 311-miles worth of tunnels.
Dr Daphné Richemond-Barak, an expert on underground warfare who teaches at Israel's Reichman University, said Hamas militants "perfected the art" of tunnel building.
She told the : "First of all, Hamas has had plenty of time to booby-trap the entire network.
"They could kidnap [the soldiers in surprise attacks]. And then you have all the other risks - running out of oxygen, fighting the enemy in one-on-one combat, and rescuing wounded soldiers becomes virtually impossible.
"Even if you don't go inside the tunnel, to secure an area where you suspect that tunnels might be present is very different from just securing an area in general.
"Here, you have to secure something that is invisible."
A counter-terrorism expert has warned because of this, hostages snatched by Hamas gunmen could be hidden in the tunnels, as Yocheved Lifshitz was.
Author Samuel Katz, who spent years observing elite special units of Israel's Defence Forces, said there are multiple locations where captives could be held and described it as "uncharted territory."
Meanwhile, Israel continues to blitz the Gaza Strip with renewed intensity as their expected ground invasion looms ever-nearer.
Gaza's health ministry says more than 5,000 have been killed since Israel began its bombardment of the densely-populated enclave.
In the past 24 hours, the IDF claims to have hit 400 targets, including several Hamas commanders, while their tanks and troops swarm close to the border.
