Despite the great public attention paid to the problem of subterranean warfare, this does not mean that subterranean warfare is the major strategic threat to Israel.
Subterranean warfare has appeared many times in the Arab-Israeli context, and the IDF and the Ministry of Defense have dealt with various aspects of the phenomenon of subterranean warfare for many years. On rare occasions Hizbollah chose to operate underground during the years the IDF controlled the security zone in Lebanon. In the Second Lebanon War, a force from the Maglan special forces unit conquered a fortified Hizbollah dugout adjacent to the Shaked post; two IDF soldiers and five Hizbollah operatives were killed in the battle. After the war, Hizbollah built an extensive system of concealment and military tunnels within the villages, and possibly tunnels for cross-border penetration as well.
During the second intifada, the Palestinian terrorist organizations in the Gaza Strip made extensive use of tunnels for smuggling weapons from Egypt to the Gaza Strip and for attacking IDF forces in Gush Katif. Digging a tunnel is estimated to take about three months and costs about $100,000. Such tunnels can be concealed so that their openings are inside houses or greenhouses, and can be dug in advance without being used until the crucial time. The IDF launched many raids against the tunnels, and by June 2004 had destroyed over 100 of them. A special heavy piece of equipment, called a trencher, was acquired and used to dig a trench along the Philadelphi axis. Shafts were dug at random places into which explosives were inserted in the hope of making the tunnels collapse, and rows of houses close to the Rafah road were demolished. The problem, however, was not solved.
Past significant attacks included the booby-trapped tunnels in the IDF’s Termit outpost, in which three soldiers were wounded in September 2001; the booby-trapped tunnel in the IDF’s Orhan outpost, in which one soldier was killed and five wounded in June 2004; and the attack on the Joint Verification Team (JVT) outpost in Rafah in December 2004 in a powerful booby-trapped and cross-border tunnel attack, which left five soldiers killed and six wounded and was considered the most deadly tunnel attack during those years. Hamas’ best-known offensive tunnel, whose exit was 100 meters inside Israeli territory near the Kerem Shalom border crossing, was used on June 25, 2006 in an attack by a terrorist squad that killed two IDF soldiers and kidnapped Gilad Shalit.
Between the years 2006-2008 In October 2006, IDF forces demolished from smuggling tunnels and offensive tunnels from the Gaza Strip. In November 2008, a paratroopers battalion commanded by Yaron Finkelman operating in Operation Double Challenge killed six terrorists and demolished the opening of a tunnel concealed within a building 300 meters from the fence on the Gaza Strip border.
The IDF'S tunnel rats
Already in the early years of the twenty-first century, the IDF organized the Samoor (“weasel”) company for combating hidden weapons caches and tunnels, as part of the Yahalom Special Operations Engineering Unit of the IDF Engineering Corps. The unit is trained and equipped with means to operate within tunnels, including communications and breathing systems. Actually, the IDF prefers to avoid entering tunnels it has detected, if possible, because the attacking side has no advantage in a tunnel. This capability is designed for a scenario in which a soldier has been kidnapped, or in order to attack the enemy’s underground command and control positions.
Operation Protective Edge's Subterranean warfare
During the entire period that included Operations Cast Lead and Pillar of Defense, not much tunnel warfare activity was recorded, but in November 2013, IDF forces destroyed two cross-border tunnels. In March 2014, the IDF demolished another cross-border tunnel. Tunnel warfare began even before Operation Protective Edge was declared, during the escalation that took place following Operation Brother’s Keeper. On July 6, 2014, in response to rocket fire from the Gaza Strip, the IDF took preventive action against a cross-border tunnel in the Rafah area that led to the death of six Hamas operatives.
As a result, Hamas intensified its rocket fire, further escalating the conflict and leading the IDF to launch Operation Protective Edge on July 8, 2014. An attempted attack on July 17 by 13 terrorists emerging from a cross-border tunnel near Kibbutz Sufa was foiled, and led to the beginning of the land-based operation. During the land campaign, brigade combat teams, including infantry, armored forces, and combat engineers engaged in the detection and demolition of both combat tunnels within the Gaza Strip and cross-border tunnels.
During Operation Protective Edge, Hamas and Islamic Jihad operatives carried out a number of attacks in Israeli territory using cross-border tunnels. Terrorists attacked an IDF pillbox tower near Nahal Oz, killing five soldiers. On August 1, 2014, a Hamas force violated the ceasefire, killing three Givati Brigade soldiers, and escaped through an offensive tunnel to Rafah, taking with them the body of First Lieutenant Hadar Goldin. A total of 34 cross-border tunnels used by Hamas were destroyed. The tunnels detected by the IDF during Operation Protective Edge were complex tunnels, with a number of entry and exit shafts. The main tunnel route was often split, and sometimes there were parallel routes. For this reason, dealing with the tunnels was no simple task.
As soon as a tunnel was detected, IDF forces took action to isolate the operating area and detect its additional shafts and branches. The Special Operations Engineering Unit planted explosives in order to demolish the tunnel. A number of methods were used to demolish tunnels during Operation Protective Edge, including aerial bombardment using JDAM bombs (called “kinetic drilling”), using water to make the tunnel collapse, and using liquid explosives by a special system dubbed “Emulsa.” In addition, elite IDF units were trained to fight within tunnels as “tunnel rat” units. In retrospect, the IDF learned that aerial bombardment of the tunnel shafts made it harder to detect the tunnels themselves.
The tunnels have been classified as a strategic threat, with the impression given that this is the gravest threat facing Israel. Arguments have since been made that the defense establishment is responsible for a strategic failure, and there have even been demands for an investigative commission on the matter. There is no doubt that the tunnels are a serious problem. despite the great public attention paid to the problem of subterranean warfare, this does not mean that subterranean warfare is the major strategic threat to Israel. It is merely one of many kinds of warfare. In other words, the issue is currently in the headlines, but long term thinking should not be distracted by momentary criticism.
The Author is the Military & Strategic Affairs and Cyber Security Program Coordinator at the Institute for National Security Studies (INSS) in Tel Aviv.
(The article was published in "The Jerusalem Post", August 16, 2016)