When Israel needs to fight Hamas in its tunnels, it turns to an elite band of commandos called the Yahalom unit

• Hamas maintains a massive tunnel network under Gaza where it hides weapons, ammo, and people.
• To engage this threat, the IDF has an elite band of troops who specialize in tunnel operations.
• Meet the Yahalom unit.

The Hamas militant group has a sprawling network of tunnels underneath the Gaza Strip that is so vast that Israel has referred to it as the "metro" of the coastal enclave. It is a serious challenge that only certain Israeli forces are trained to face.

Clearing out the Hamas tunnels is one assignment for the Israel Defense Forces (IDF) amid its ongoing ground invasion of Gaza, now a little more than a week old. To effectively carry out this task, the military has a elite band of commandos who are trained for underground warfare and other subterranean operations known as the Yahalom unit. 

Yahalom is part of the IDF's Combat Engineering Corps and is made up of different specialized companies that are responsible for tunnel warfare, engineering reconnaissance, explosive ordinance disposal, and unconventional weapons. The unit was created in 1995 and doubled in size after the 2014 Gaza War — known in Israel as Operation Protective Edge — to deal with the growing threat posed by Hamas' tunnels. 

"The unit's role includes special sabotage missions, demolition and explosion of buildings, sabotage of enemy infrastructure, handling of explosives, preparing explosive devices and bombs, neutralizing enemy explosive devices, clearing complex minefields, locating and destroying terror tunnels," the IDF said in 2021. "At times, the unit uses robots and many remote controlled devices, without endangering human life."

According to the Yahalom Foundation, an organization that consists of soldiers who formerly served in the unit, enlisting is a "rigorous" process that involves a medical profile and tryouts that last for four days. What follows is a "long and arduous" training program that lasts 16 months and includes education in explosives and demolition, combat engineering training, counterterrorism training, Israeli martial arts training in Krav Maga, and the development of other skills like parachuting and repelling. 

Yahalom, which mostly works in secret, has already been put to work since Israel began its expanded ground assault of Gaza last week. On Friday, for example, the IDF said Yahalom soldiers working in tandem with other units destroyed Hamas tunnels during "special operations" inside the strip. 

"The troops uncovered tunnel shafts, rigged them with explosives and neutralized the tunnels," the military said at the time. It published footage of Israeli soldiers inspecting a tunnel shaft that they discovered near Beit Hanoun, in the northeastern corner of Gaza. The IDF also published above-ground footage showing explosions from the tunnels.

Hamas has claimed in the past to have more than 300 miles of tunnels underneath Gaza. Israel says they're used to hide and store collections of weapons and ammunition, facilitate the covert movement of militants, and function as command centers and bunkers. With access points hidden in places like schools and hospitals, and exit points within Israeli territory, the military considers the tunnels to be a grave threat to civilians. 

The tunnel problem is one that has significant relevance for the urban fight that's unfolding in Gaza as Israeli forces encircle the enclave's main city. Military experts say Hamas could use the tunnels defensively to protect assets such as personnel and equipment and offensively to carry out surprise assaults and guerilla-style attacks on Israeli troops. 

Col. Yaron Beit-On, who served as the Yahalom commander in 2016, said at the time that "the main challenge of underground warfare is that the enemy has no above-ground signature," making it difficult to collect intelligence. "Hamas views warfare underground just as it would aboveground, utilizing defense, offense, and retreat," he remarked.

Yahalom and other IDF units have a wide array of tools at their disposal to use for tunnel operations, John Spencer, chair of urban warfare studies at West Point's Modern War Institute and a former US Army infantry soldier, wrote in a recent analysis on Hamas' subterranean network. These include drones and robots, ground and aerial sensors, drilling equipment, night-vision systems, and radio technologies. Clearing the tunnels though is still a difficult task.

Possibly further complicating the underground fight is that fact that Hamas is believed to be hiding the more than 200 hostages that the militant group captured during the October 7 terror attacks across southern Israel. To protect the hostages, assuming that is where they are, the IDF will have to be careful and calculated in its actions. It will be unable to just destroy the tunnels and keep moving.

"You don't know what's down there," Spencer told Insider in a recent interview, explaining that Hamas is holding hostages in the tunnels and uses civilians as human shields. "That's going to exponentially challenge this normal underground nightmare."