While the Israeli government has been bombarding Gaza for weeks in response to Hamas’ brutal terrorist attack in October, a more covert military network has been preparing to take down Hamas.
Out of the spotlight, an elite combat engineering team of the Israeli Defence Forces (IDF), the Yahalom Unit, has been preparing for a drawn-out fight with Hamas in the extensive maze of tunnels the terrorist organization has dug out underground.
The Yahalom Unit is trained to explore the roughly 300 miles of underground tunnels the terrorist organization has used to smuggle in goods for military and strategic purposes. Over the years, Hamas has relied on its tunnels to avoid Israeli monitoring and move weapons such as rockets to launch surprise attacks against Israel, according to the IDF.
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Hamas fighters are believed to have used their secret tunnel exits—a network the Israelis call the “metro”—to launch their attack on Israel on Oct. 7, which caught the military and intelligence community by surprise, triggering Israel to declare war on Hamas.
The next phase of the war is already underway, Israeli Prime Minister Benjamin Netanyahu announced last week.
“We are only at the start,” Netanyahu said. “We will destroy the enemy above ground and below ground.”
The challenge facing the Yahalom Unit is like grasping at targets in the dark, experts say. Hamas can use the tunnels to strike back at Israel with surprise attacks, and the advanced technology Israel might use above ground is all but useless underground. Hamas terrorists could also use the tunnels to escape from Israeli forces, according to John Spencer, who has toured with the IDF to observe Yahalom training in Israel.
The underground is “a very effective… way to hide your capability, protect your capability, and also use asymmetric means—as in not going toe to toe with the other military by using the underground to pop up and surprise attacks and pop back down and conserve your capability,” Spencer, the chair of urban warfare studies at the Modern War Institute and a combat veteran, told The Daily Beast. “That is a primary strategy of Hamas.”
“The main challenge of underground warfare is that the enemy has no above-ground signature,” said Col. Yaron Beit-On, who was commander of the Yahalom Unit at the time, in 2016. “The fact that the enemy is hidden and collecting intelligence is complicated and difficult.”
(The IDF has requested that only first names of people in the unit be used, though articles published at the time shared the commander’s full name.)
The mission is not a cookie-cutter one that IDF soldiers can rehearse from playbooks. Each tunnel presents unique challenges and potential surprises, Lt. Hezi said in 2016.
“No two tunnels are the same. The first person to enter the tunnel has to improvise,” Hezi said. “This is exactly what we train for—to be prepared for any situation, whether it be a terrorist or an explosive. When you see the inside of these terror tunnels—that’s when you suddenly understand how big of a threat we face.”
The IDF has tried to make Yahalom soldiers’ missions less dangerous in recent years, using robots in tunnels to search for terrorists or booby traps, for instance.
Israeli Minister of Defence Yoav Gallant meets soldiers on the Israeli border with the Gaza Strip in Sderot, Israel.
Amir Levy/Getty ImagesIn addition to equipment to help them work and fight in these subterranean labyrinths, soldiers need gear to help them breathe and see properly.
Soldiers also have to be prepared to deal with gas attacks, said retired U.S. Army Lt. Gen. Mark Schwartz, who served as the United States Security Coordinator for Israel and the Palestinian Authority from 2019-2021.
“What I’d be really worried about is being able to deploy some type of field expedient gas that affects the filtration systems that you need to be on when you’re operating underground,” Schwartz said, warning that could trip up the IDF’s plans to run operations underground. “You have protective equipment that you can wear, but I think what can really slow this down, or cause the IDF to rethink things, is if they come across this.”
Israel has said that its main goal is to eliminate Hamas. If that’s the case, the pressure on the Yahalom Unit will be unprecedented.
Israel has worked to target and eliminate tunnels in previous campaigns, including in 2008 and 2014, in a campaign the IDF called Operation Protective Edge. Then, Israeli service members located, mapped, and cleared tunnels, planting explosives to destroy them.
But hundreds of tunnels remain. Of the roughly 300 miles of tunnels Hamas is suspected to have, Israel said it has destroyed only 60.
And since then, Hamas has only likely doubled down, building more.
The mission this time around is less clear-cut, as hundreds of hostages Hamas kidnapped on Oct. 7 remain inside Gaza: Destroying tunnels outright before hostage recovery missions take place—and before the U.S. and Israeli intelligence communities have determined where, exactly, Hamas is holding the hostages—risks endangering their lives.
The IDF has not explicitly stated what the Yahalom Unit’s mission is—but they are likely not working on mapping Hamas tunnels given the ongoing war. Some suggest the mission may be focused on hostage recovery, and then destruction.
Israeli army soldiers wait at a position in the upper Galilee region of northern Israel near the border with Lebanon amid increasing cross-border tensions between Hezbollah and Israel as fighting continues in the south with Hamas militants in the Gaza Strip.
Jalaa Marey/Getty Images“These specialized units are going to be put in very risky situations,” Schwartz said. “But it’s all part of rooting out Hamas, and trying to find the hostages.”
Netanyahu said in his recent speech announcing the next phase of war that Israel’s goals include both destroying Hamas and rescuing hostages.
Hamas could be moving the hostages around, U.S. officials have admitted, a fact that complicates the underground endeavor.
By unleashing Yahalom soldiers into the underground network Hamas has built, the IDF could use the tunnels to corner the terrorists holding hostages, Schwartz said.
“Something that’s unique here is the number of hostages they have,” Schwartz said. “From just the logistics of keeping them and moving them away from if they see the IDF encroaching areas they’re being held and they don’t want to risk their being liberated by the IDF, then that may cause them to move, that may in itself provide opportunities potentially for finding them.”
Netanyahu visited the Yahalom Unit for a briefing and update last week on their work since the beginning of the war, including a demonstration of the unit’s underground capabilities, and during his comments at the briefing, he returned to efforts to destroy Hamas.
“We stand before the next stage, it is coming. You know it and you are part of it; you are part of the vanguard. I greatly appreciate what you know how to do,” Netanyahu told the soldiers. “We have only one mission—to smash Hamas. We will not stop until we complete it, with your help. I rely on you; the people of Israel rely on you. I am proud of you and I salute you."
Weasel in
The IDF has been working with a laser focus to train up soldiers in the Yahalom Unit to deal with the tunnels. Just one year after Operation Protective Edge, the IDF announced Yahalom would be growing in size in a recognition that the IDF needed to step up to grapple with the Hamas tunnel infrastructure after being caught under-prepared in 2014.
In the years since, Israel has been working to train the unit on joint operations in times of peace and during hostilities, as well as on complex navigation exercises, emergency campaigns, and in mock tunnels.
The force has been receiving “very professional training and education” on Hamas tunnels for years, said Spencer.
“I got a tour of various facilities in southern Israel. I got to observe a demonstration of capabilities and see other soldiers who were in training under the Yahalom,” Spencer told The Daily Beast, adding that it was not a “theoretical” training.
He described a training session in which photos and material from previously discovered Hamas tunnels were used to train IDF soldiers on the challenges ahead.
Last year, some Yahalom soldiers conducted training to operate across domains, including urban ones, coordinating with combat helicopters, emergency evacuations, intelligence, and other logistics, the IDF said.
The Yahalom Unit is divided into several companies with different specialties, including the Samur unit, or the “weasel” unit, which focuses on entering, clearing, and eliminating tunnels. The Sayfur company focuses on training to handle unconventional weapons, while the Yael unit focuses on clearing and demolition.
Soldiers have in the past undergone nine months of commando training followed by months of specialized training.
Even with all the tools and training, the scale of the operation may still spell trouble for the soldiers.
While Israel has worked to understand Hamas’ tunnel network, the landscape underground may have changed in recent years, providing surprises for IDF soldiers, warned Spencer. As Hamas has likely continued digging new tunnels, their construction might have evolved or may pose other new challenges throughout Gaza.
“I do believe they probably have more than those 500 kilometers [approximately 300 miles]… just because this has been such a vital part of their strategy and their preparation. Much like October 7 was a surprise, they clearly are going to be surprised to see the underground.”
“Hamas has continued to evolve, and you have to assume that means the tunnels as well,” Spencer said.
The exact makeup and size of the Yahalom Unit is unclear, but they are likely not a massive unit given how specialized they are, said Schwartz.
“Typically these specialized units are not large,” Schwartz said.
And though they have been training for years, the IDF may run the risk of exhausting its well-trained Yahalom fighters in the days ahead in a protracted, drawn-out urban-warfare fight with Hamas, particularly given the scale of the operation at hand, Spencer warned.
“While I am very impressed by IDF capabilities, it is a question of being able to adapt to surprises and being able to deal with the size of the problem—this is not one tunnel that a specialized group can respond to. These are hundreds of tunnels,” Spencer said. “You may run out of specialized forces, and you’ll have untrained, under-equipped forces that are having to deal with tunnels.”
There are indications that the next phase of the war will be a drawn-out affair.
Israeli Defense Minister Yoav Gallant has acknowledged that the war could go on for months.
Those familiar with the Yahalom Unit’s operation appear to expect the mission to last at least through the winter. The unit’s foundation has been seeking outside funding to ensure the unit’s work can continue as the war progresses through colder weather. The foundation has made requests for donations that would buy the unit functional winter clothing, such as camouflage suits. In return for donations in the ballpark of $150-$250, according to Israel Today, a Zionist news agency, the Yahalom Foundation has been offering supporters a hat with a Yahalom unit patch, and in some cases an IDF bag.
The IDF training for underground warfare is likely going to be an ongoing effort behind the scenes, even as hostilities progress, so that Israel can build up a pipeline of soldiers well-versed in these operations, said Schwartz.
The sheer size of the tunnel network could “tax” the Yahalom unit’s full capability, requiring all hands on deck, Schwartz said.
“That pipeline is being created while you’re in combat,” Schwartz said. “That’s extremely hard.”
