As Israeli troops push southward through the Gaza Strip, there are almost daily reports of new tunnel shafts, lavish bunkers, subterranean weapons factories and storage facilities being discovered. Yet recent estimates by Israeli and U.S. officials suggest that only a small fraction of the vast and intricate underground system built beneath the Palestinian enclave by the Hamas terror group has so far been demolished.

Last week, at the Munich Security Conference, Sen. Mark Warner (D-VA), chair of the Senate Intelligence Committee, told reporters that Israel had only been able to secure a “stunningly small” amount of the tunnels that Hamas fighters are using in Gaza. His comments followed a Wall Street Journal report last month quoting U.S. and Israeli intelligence sources as saying that between 20%-40% of the tunnels that snake below the Strip had been “damaged or rendered inoperable” since the start of the fighting, sparked by Hamas’ brutal terror attack in southern Israel on Oct. 7.

While the IDF is certainly detecting and even mapping a growing portion of what observers believe could be more than 300 miles of underground passageways – roughly half the New York City subway system – it is not clear exactly how much progress has made in eliminating the threat posed by this elaborate subterranean network, which Israelis often refer to as the “Gaza metro.”

IDF spokesman Lt. Col. (res.) Peter Lerner told Jewish Insider this week that no formal assessment had been made public of how much of Hamas’ tunnel system had been destroyed or neutralized, emphasizing instead that the goal was quality over quantity.

“The magnitude is less important than what actually is the makeup of that magnitude,” he explained, highlighting that the army was focused more on “dismantling key components of the tunnel infrastructure that gives [Hamas] a tactical and operational advantage.”

In northern Gaza, Lerner described how underground command-and-control centers used by the terror group had been obliterated, forcing Hamas’ fighters above ground, while further south, in the city of Khan Younis, the detection of hideouts utilized by senior Hamas leaders, including Oct. 7 mastermind Yahya Sinwar, as well as cells where Israeli hostages were held, have left the terror group “in a constant state of threat and pursuit.”

He also said that the IDF had targeted rocket launchers, weapons storage and manufacturing facilities hidden below ground, reducing the overall number of rockets being fired into Israel significantly over the past few weeks.

“It is all part of an organism,” Lerner said. “We are cutting it down slice by slice, location by location, which handicaps Hamas’ ability to operate freely.”

Identifying the mileage of the tunnel system, the spokesman clarified, was more to show the “effort and expense of Hamas’ industry of building its terror tunnel network, which was designed to give them that tactical and operational advantage and, in some places, even a strategic advance.”

“Dismantling that capability means that all of its efforts and all of the money that went into this project is basically wasted,” Lerner added. “It also means that they are less competent in both their ability and conduct.”

Israel has been grappling with the threat posed by Hamas tunnels since the late 1990s, when Gaza was still under full Israeli military control and Israeli civilians lived in the Strip. As early as 1999, incidents of Palestinian terrorists using underground passageways to infiltrate army bases and even communities were reported. In addition, at that time, Israel was aware that numerous tunnels snaking beneath the Strip’s border with Egypt were being used to smuggle goods and weaponry into the territory.

By the mid-2000s, cross-border tunnels were also detected beneath Gaza’s perimeter with Israel. In 2006, an attack tunnel was used in the kidnapping of Israeli soldier Gilad Shalit. In 2014, Israel’s previous major war with Hamas, the terror group used tunnels to infiltrate civilian communities in southern Israel and attack Israeli forces battling inside the Strip.

Following that war, Israel focused its efforts on developing technology that could detect additional cross-border attack tunnels and spent millions of dollars on an advanced underground barrier designed to block the threat of future infiltrations. The military also began training some of its elite units in the art of underground fighting.

Still, over the past four months of fighting, the IDF has appeared surprised at discovering the extent of the elaborate, multimillion-dollar labyrinth built by Hamas – a system that Palestinians refer to as “lower Gaza.”  

Daphne Richemond-Barak, author of the 2017 book Underground Warfare and a professor at Reichman University in Herzliya, told JI that taking the fight underground was not only a tactical advantage for Hamas but also a carefully planned “strategic asset.”

“Above ground, Israel has superiority over Hamas, but underground it is a level playing field that even gives Hamas an upper hand because they know the layout of the tunnel network,” she said, adding that, “The most significant mistake Israel has made is to see this [the tunnels] as a tactical asset and not as a strategic asset.”

“I would say it is absolutely and completely necessary for Israel to destroy all the tunnels and not just neutralize them,” Richemond-Barak said. “Neutralizing them is just a temporary measure, while a destruction is a hard kill that leads to the collapse of its structure – its walls and its ceiling, making it totally unusable.”

“We have heard the IDF claiming many times that they destroyed the opening of a tunnel, but that doesn’t mean anything,” she continued. “The opening is only the point where the tunnel meets the surface; what needs to happen to eliminate the threat is for the tunnel itself to be destroyed – what’s the point of destroying the opening of the tunnel when the tunnel itself can still be used?”

Richemond-Barak pointed out that tunnels can change purpose and usage over time. While they might be utilized in one way by a certain group, they could be inherited by other factions who might adapt them and use them in a different way.

“To hear that the Israeli army views some tunnels as strategic and others as non-strategic is completely counter to how I believe tunnels should be dealt with,” she concluded. “Haven’t we learnt anything in the past four months? As long as there is a hole in the ground and a tunnel behind it, then it is a threat to our forces and a threat to Israel.”