The tunnels have become a major headline of the Gaza war. Hamas leaders and some 20,000 fighters are using the tunnels, which are like an underground fortress. In the past ten years, the Israeli Army realized that it could not eliminate the tunnel phenomenon. Rather, the tunnels have since grown and become more developed. At first, they were built to allow Hamas fighters to counter Israeli ground attacks and ambush their troops. Meanwhile, Hamas took its time in enlarging its network of tunnels in Gaza. The tunnels now total around 1,300, reaching around 70 meters underground and extending 500 kilometers.
Tunnel warfare is not new. From medieval mining, its long history extends through the subterranean component of the World War I battles of the Somme, Vimy Ridge and Messines. US Army fought in the massive underground complexes of the Vietnam War. Later al-Qaeda and ISIS tunnels in Afghanistan, Syria, and Iraq.
In Vietnam, where North Vietnamese and Viet Cong forces used miles of tunnel networks to protect their supply routes, military forces, and bases in places like Cu Chi, the problem became so severe that it forced the development of new tactics – sending US soldiers, called tunnel rats. Building the network has also come at a cost to the local population. The IDF has accused Hamas of diverting millions of dollars given to Gaza in aid to pay for the tunnels as well as tens of thousands of tons of cement intended for rebuilding homes destroyed in previous wars. The network boasts rest areas, meeting rooms, and sleeping areas.
Surprise Attack
It is fully equipped and features a modern ventilation system. It holds storage for food, medicine and fuel and has its own encrypted telecommunications system that Israel has failed in deciphering, as demonstrated in Hamas’ surprise attack on October 7. Israel says it is striking parts of a secret labyrinth of tunnels built underneath the Gaza Strip by Hamas, as it continues to retaliate for the Palestinian Islamist militant group’s unprecedented cross-border attack.
Military experts call them a soldier’s nightmare, and caution against entering the stuffy, narrow passages, which are low on oxygen. Commanders who train for urban warfare divide the battlefield into four planes. One is the sky above cities, increasingly thick with drones. Next are the buildings, offering vantage points and hiding places. A third is the streetscape: the lattice of roads, alleys and paths. It is the fourth—the tunnels lying beneath that will present the greatest challenge to the Israel Defence Forces (IDF). Experts say soldiers who enter tunnels can quickly lose their bearings and some fall victim to vertigo. It is very difficult to assess the size of the network, which Israel has dubbed the “Gaza Metro”. IDF warplanes could also drop “bunker busting” bombs, which penetrate deep into the ground before detonating. However, they pose a risk of collateral damage due to the dense urban terrain.
The cross-border tunnels tend to be rudimentary, meaning they have barely any fortification. They are dug for a one-time purpose – invading Israeli territory. The tunnels inside Gaza are different because Hamas is using them on a regular basis. They are definitely equipped for a longer, sustained presence. They are equipped with electricity, lighting and rail tracks. Hamas has had plenty of time to booby-trap the entire network. They could just let the soldiers enter into the tunnel network and then eventually blow up those sections.
To gain a position to fight in the tunnels, Israel has to identify as many entrances as possible. For a system believed to be up to 500km (310 miles) long, those probably number in the tens of thousands. Most are hidden, inside residential buildings, garages, industrial facilities, warehouses, under rubbish dumps. The tunnel builders, Hamas, have a huge advantage as they know the network. Israeli software might offer hints connecting patterns of movement to reveal that two points are probably connected, but it does not reveal the underground routes, directions, or junctions. To map the tunnels with whatever degree of accuracy, commandos must get inside, facing huge dangers and difficulties. The first is technical: Down there, GPS positioning devices are useless as satellite signals cannot penetrate the soil. This a plus point for Hamas.
Weasels in action
Since 2004, the IDF has had a sub-unit dedicated to entering, clearing and destroying tunnels. Part of Yahalom, the special forces unit of the Combat Engineering Corps, the tunnel sub-unit is called Samur, the Hebrew word for “weasel.” 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.
They will not be able to use radios to communicate with units on the surface, so they will have to use field telephones, technology from over 100 years ago. In the past, Samur released videos of its tunnel-capable robots that might be useful as trailblazers, reconnoitering passageways and sending back night-vision videos. But they can be used on one level only, as they cannot climb ladders or obstacles. In 2020, Israel found a Hamas tunnel that descended 230 feet below the surface, the deepest found up to that point.
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 unit focuses on training to handle unconventional weapons, while the Yael unit focuses on clearing and demolition. By unleashing Yahalom soldiers into the underground network Hamas has built, the IDF could use the tunnels to corner the terrorists holding hostages. Many of the high-tech advantages Israel enjoys above ground disappear when soldiers go underground. Regular night vision goggles don’t work, communication is limited, and soldiers must bring their oxygen supplies. The current operation is expected to use ground robots and drones that will go in first and map what’s ahead. Soldiers will follow. Soldiers who can tolerate the claustrophobic environment inside the tunnels are recruited to become “weasels.” IDF has prudently determined that the best candidates for the job are those who are introverted.
Flood Tunnels
Israeli command knows that its advantage in technology and weapons is considerably higher on the ground than under it, so it would prefer to flush Hamas out and fight on the surface. To do so, it may use chemical agents such as teargas, a little of which goes a long way in tight tunnels. Water has often been used in the past to flood tunnels and force their occupants out but there is simply not enough water in Gaza.
In 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. The tunnels are laced with wires and cables that carry electricity, internet, telephones and military lines. Hamas may have observation and detection devices that would let them know where the Israelis are so they can remotely explode charges in that exact spot. Israelis cannot simply cut all the wires because some detonators might be triggered when their electrical supply is severed.
A weapon fired in compact spaces of tunnels, even a rifle, can produce a concussive effect that can physically harm the firer. A single defender can hold a narrow tunnel against a much superior force. Hamas may also ignite incendiary compounds that deprive occupants of oxygen and spread as high-speed flash fires or create thick, often toxic smoke. This would keep the tunnels mostly undamaged, allowing the Hamas fighters to use them after they force the enemy out. Defensively, Hamas will use tunnels to escape IDF observation and attack. Any Hamas military capability that survives Israel’s current air campaign will mostly be deep underground.
(The writer is the author of Target Secured- Police Special Task Force)
Dishan Joseph