For decades, Hamas’ tunnel network has been one of the most important elements of its campaign against Israel.
But it wasn’t until the Oct. 7 war that the vastness and sophistication of the underground grid was fully understood. Its complexity has raised questions about the role Iran may have played in helping develop and build it.
Along with Hamas arsenal, the tunnels are now tied to discussions over the U.S. peace plan. Israel insists it will not withdraw before Hamas is disarmed and the tunnels are destroyed. Hamas has said it won’t disarm until Israel withdraws from Gaza.
Destroying the tunnel network isn’t a simple process either. The warren extends across northern, central and southern Gaza. It includes passageways, rooms, storage areas, command centers, and electrical and ventilation systems. Fighters could stay there for days if not longer.
In December 2023, the Israeli military said it had identified more than 800 tunnel shafts since the beginning of the war and destroyed more than 500 of them. It also described routes that it said stretched for nearly 10 kilometers (6.2 miles) and connected different areas of the Gaza Strip.
In its Gaza campaign, the Israeli military used multiple tactics to root out its enemies from the tunnels. Forces took control of entrances and exits, mapped routes with robots, flooded some parts and used explosives to bury others.
Israel’s control of large areas of the Gaza Strip, particularly in Rafah in southern Gaza and along the Salah al-Din, or Philadelphi, corridor, has reduced Hamas’ ability to use tunnels to cross the border, said Palestinian military expert Maj. Gen. Samir Abahara.
But he told MBN that the network’s complex structure — the varying depths, multiple routes and use of reinforced concrete — make completely destroying it a complicated and costly endeavor.
Evidence of Iranian Support
Retired Egyptian Maj. Gen. Wael Rabie, who is now an adviser to the Center for Strategic Studies in Cairo, told MBN that Hamas used the tunnels to counter Israel’s air and technological superiority. The network allowed fighters to move unseen by Israel’s continuous aerial surveillance.
There are tunnels used for offensive and defensive operations; tunnels used for supply and communications and for transporting fighters, ammunition and provisions; and tunnels used for command-and-control that housed leaders and operations centers.
The size and complexity of Hamas’ tunnel network indicate some level of Iranian support, Abahara and Rabie said.
Abahara said Palestinians had developed the basic know-how to dig tunnels locally over decades, beginning with commercial smuggling tunnels along the border with Egypt.
Iran’s role, he said, was to provide financial support, training and weapons to Hamas that turned a tunnel network into a military tool.
Hezbollah, which Washington designates as a terrorist organization, transferred some of its experience in southern Lebanon to the Gaza Strip, particularly techniques for reinforcing walls and ceilings, ventilation and managing closed communications networks underground, Rabie said.
Hamas later developed its own digging and concrete-reinforcement methods adapted to Gaza’s geography, he said.
In its 2023 terrorism report, the State Department estimated that Iran provided up to $100 million annually in combined support to Palestinian armed groups, including Hamas and Islamic Jihad. In August 2017, Hamas itself said Iran was its “biggest supporter” militarily, providing money and weapons, after relations between the two sides were restored following years of tensions linked to the Syrian war.
Different Uses
After the Oct. 7 attack, the U.S. Treasury Department imposed sanctions on officials and networks it said were involved in transferring money from the Quds Force to Hamas and Islamic Jihad, both of which Washington designates as terrorist organizations.
In February 2024, the Israeli military announced that it had found documents and money inside tunnels in Khan Younis that it said showed Iranian transfers to Hamas. It later published additional documents that it said were found inside a tunnel network linked to the group’s leaders and described them as evidence of financial ties between Hamas and the IRGC.
Israel has sought to counter that support by developing technologies to detect underground digging and by constructing a barrier that extends above and below ground along its border with Gaza.
In June 2006, the kidnapping of Israeli soldier Gilad Shalit demonstrating the military capabilities of cross-border tunnels for Hamas. But the digging had begun decades before.
Samir Ragheb, head of the Arab Foundation for Development and Strategic Studies, said tunnels have extended from underneath Rafah since Egypt and Israel signed a peace treaty in 1979 and demarcated their border in 1982. The demarcation divided Rafah into two sections, Egyptian and Palestinian, separating families that had lived on both sides of the border.
According to Ragheb, the tunnels were not initially intended for military purposes but for social and commercial reasons. They connected families and facilitated trade between the two sides of Rafah.
The first official Israeli discovery of a tunnel in the area was recorded in 1983, he said.
During the 1990s, tunnel use expanded as restrictions on the movement of people and goods tightened. The tunnels increasingly became a means of smuggling goods and weapons, and their activity grew further after the outbreak of the second Palestinian intifada in 2000.
The tunnel network Israel encountered in the 2023 war did not emerge all at once. It was the result of a process spanning more than four decades — from rudimentary passageways between the two sides of Rafah, to smuggling and commercial tunnels, and eventually to a military network containing routes for combat, supply, command and control.
Adapted and translated from the original Arabic.
