Editor’s note: Peter Bergen is CNN’s national security analyst, a vice president at New America, a professor of practice at Arizona State University and the host of the Audible podcast “In the Room With Peter Bergen,” also on Apple and Spotify. The opinions expressed in this commentary are his own. Read more opinion at CNN.
The tunnels built by Hamas in Gaza are likely to be a key target of the Israeli offensive sparked by the October 7 terror attack on southern Israel. Hamas is believed to be housing underground a considerable number of fighters and weapons, along with an unspecified number of the estimated 239 hostages that the Israeli government says that Hamas has taken.
A professor at the Lauder School of Government, Diplomacy and Strategy at Reichman University in Herzliya, Israel, she founded the International Working Group on Subterranean Warfare.
During the Vietnam War, the Viet Cong used tunnels extensively to hide in and to fight US troops, while during World War I, the British launched large-scale attacks from tunnels against the Germans, such as one at the Battle of Messines in Belgium in 1917 that killed some 10,00 German soldiers.
Richemond Barak began writing her book in 2013 when a sophisticated cross-border tunnel about a mile long and at a depth of up to 60 feet was dug by Hamas from the Gaza Strip into Israeli territory, where it was subsequently discovered.
In the decade since, she has done extensive research into Hamas’ tunnel system as well as the underground network built by Hezbollah.
The latter will be important to understand should the regular exchanges of fire this month between the Iran-backed militant group and Israel intensify into a full-blown war on Israel’s northern border with Lebanon.
Peter Bergen: What’s it like inside a Hamas tunnel? What does it feel like? What does it smell like?
Daphné Richemond Barak: You find yourself in this moist, dark, terrifying, claustrophobic environment where you never know what’s around the corner, literally.
Also, it can get very cold at night, and it’s suffocating. There’s not a lot of air. If you’re going to be there for a long time, you need oxygen, especially if you’re a soldier. And in some of the tunnels, you need to bend down because they’re not very high.
When you enter one of these tunnels very quickly, you lose your sense of direction completely — where you came from, where you’re going. It’s easy to get completely disoriented and confused quickly, and some people have major trouble with that.
In addition to the claustrophobia, you lose your sense of time, so you might feel like you’ve been there for two hours, but it’s only really been 20 minutes.
Bergen: How is Hamas communicating inside these tunnels? Because presumably, radio communication and that kind of thing doesn’t work.
Richemond Barak: So, cell phones, of course, are out of the question. It has implications for Hamas, which, to exploit this network of tunnels needs to figure out a way to be able to communicate among themselves, but it also has implications for the IDF (Israel Defense Forces). If they go down inside the tunnels, how do they maintain communication between the units underground but also with the forces above ground?
Bergen: The tunnel training facility that the Israelis have — tell us the history of that and how it works.
Richemond Barak: After the wake-up call of 2014 Operation Protective Edge in Gaza (Israel’s campaign against Hamas involving both airstrikes and ground raids that took 50 days), Israel started looking at the underground tunnel issue as a strategic issue.
Israeli soldiers went into Hamas’ tunnels during Operation Protective Edge, and they were not trained and not equipped, and there was combat in the tunnels.
As a result of Operation Protective Edge, Israel took a lot of measures not only for the detection techniques of tunnels but also to train in this subterranean environment.
They created elite units that are very well-versed in all aspects of underground warfare.
In addition, they started basic training in underground warfare for soldiers so they would know how to bypass a tunnel or neutralize a tunnel and then what equipment would be needed if they had to go down there. You need to be prepared for a different kind of environment but also a different kind of fight.
IDF also used simulators where you put these virtual reality goggles on, which would then take you inside the virtual tunnel. But it’s not the same as being in a tunnel. To experience it, you need to be inside an actual tunnel, and then one of the challenges you face there is decision-making: What do you do if you find a door? Do you breach the door? How do you breach the door?
Bergen: Why tunnels?
Richemond Barak: Why tunnels? The digging of tunnels is a very time-consuming and resource-intensive kind of work. It takes a long time to dig. You need to keep the location of the tunnels secret. So the point is, there’s a huge investment there. When you go inside the tunnel, this investment hits you in such a powerful way, especially in the Hezbollah tunnels, because they are near Israel’s northern border, where it’s hard rock that you must tunnel through — or more accurately in this case — excavate.
Tunnels neutralize the military capability of a more sophisticated enemy. It serves as a great equalizer between the two sides.
Bergen: Regarding Gilad Shalit, the Israeli soldier who was held hostage by Hamas between 2006 and 2011. Reading your book, I realize tunnels played an important role when he was taken. Can you explain how that happened?
Richemond Barak: What Hamas did was they used smuggling tunnels to bring Shalit into captivity, and it was a surprise because this was not what these tunnels had been used for until then. And Israel was surprised and suddenly realized, wait a second, maybe we should pay more attention to these tunnels because the kidnapping of an IDF soldier is considered a major strategic event. After all, Israel had to release some 1,000 Palestinian prisoners to get Shalit back.
Bergen: For the Israelis, one of their significant concerns now must surely be that these tunnels could be used to take additional soldiers as hostages.
Richemond Barak: Absolutely. Kidnappings of soldiers are always perceived in Israel as a strategic kind of event. So, additional kidnappings would be devastating at this stage.
Bergen: How big a role will the tunnels play in this war?
Richemond Barak: Israel understands that to eliminate or destroy Hamas’ military capabilities, this subterranean network of tunnels, where Hamas has its arsenal and command and control, needs to be eliminated. I won’t say entirely eliminated because I believe it’s impossible. But it needs to be a significant blow to this capability, much more severe than what was done during Operation Protective Edge.
It’s terrain that Hamas knows so well, in which it maneuvers with ease, and they don’t get lost inside their tunnels. It’s not that different from what ISIS did in Mosul, Iraq, or Raqqa in Syria; this was ISIS’ last-resort measure when it came to fighting the coalition fighting against ISIS. The fight moved to the underground.
But to achieve the strategic aim, which is to eliminate Hamas’ underground military infrastructure, the way to do that is not via an above-ground incursion.
Bergen: Is a dog force used by Israel inside tunnels?
Richemond Barak: Yes, dogs are trained to go into this environment.
Bergen: What about robots?
Richemond Barak: What you need for such a robot is the ability to walk in wet terrain because there’s water usually at the bottom of a tunnel. It’s moist. You need them to be able to go up ladders or staircases.
Bergen: What else might work?
Richemond Barak: High-pressure water would cause a collapse of the structures of the tunnels. It attacks the tunnel structure in a much more significant way than just flooding it with regular water. Remember that the ground can absorb some of the water.
Now, there could be civilians in the tunnels, and most likely, there could be hostages; you need to clear the tunnels first. If they’re inside the tunnel, then it’s obviously more difficult. And I wouldn’t use the high-pressure water.
Bergen: What about Hezbollah’s tunnels should the war widen?
Richemond Barak: To illustrate how difficult it is to detect tunnels, refer to Operation Northern Shield. This is the operation that Israel launched in 2018 to expose the cross-border tunnels that Hezbollah had dug.
This is after Israel had dramatically improved its detection techniques, but this is in a different kind of terrain because Hezbollah must tunnel through hard rock, whereas in Gaza, it is soft soil.
It took Israel — even though there were no hostilities — six weeks to detect six tunnels.
Even if you have intelligence, even if you’ve narrowed down the area where you suspect tunnels are located, even if you have the most sophisticated and available means of detecting tunnels, it will still take you a considerable amount of time to find the tunnels.
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