In an interview, he recalled the final days of the battle for the Iraqi city of Mosul, where Islamic State fighters hid in a series of tunnels in 2017. “Our Iraqi soldiers used bulldozers to clear out ISIS fighters who were literally dug in the rubble,” he said. “It was very, very brutal.”
Tunnels have been a part of life in Gaza for years, but they proliferated after 2007, when Hamas took control of the enclave and Israel tightened its blockade. The Palestinians responded by building hundreds of tunnels to smuggle in food, goods, people and weapons.
According to the Israeli military, the tunnels cost Hamas about $3 million each. Some are made of precast concrete and iron and have medical rooms for treating wounded fighters. Others have rooms 130 feet underground where people can hide for months.
In Israel, the tunnel system is often referred to as the “lower Gaza Strip” or “subway.”
Yocheved Lifshitz, an 85-year-old woman held hostage by Hamas for 17 days this month, described being marched for miles through a “spider’s web” of tunnels. She told reporters on Tuesday that Hamas fighters led her through the wet and damp underground corridors to “a large hall where about 25 abductees were concentrated.”
After two or three hours, they moved five people from their kibbutz to a separate room, she said.
At a news conference on Friday, Rear Adm. Daniel Hagari, an Israeli military spokesman, accused Hamas of building tunnels and other facilities under Gaza’s Al-Shifa Hospital, the territory’s largest medical center. He played a monitored audio recording and showed an illustration of the underground complex.
General Votel, who visited a tunnel controlled by the Lebanese Hezbollah militia near the Israeli border, said he was “amazed by the effort involved in building these things.”
“It wasn’t just holes in the ground, it was architecture,” he said. “They were connected to rooms and built to withstand impacts on the surface.”
As Hamas expanded the underground system, it hid the entrances to the tunnels in houses and other small buildings on the Egyptian side of the border, said Joel Roskin, a geology professor at Bar-Ilan University in Israel during his time in Israel military busy with tunnels. These tunnels made it possible to smuggle goods out of Egypt.
The tunnel system extends to the Israeli border in the north.
A decade ago, Egypt made an attempt to destroy the tunnels along its border by pouring sewage into some of them and leveling houses that obscured entrances, Mr. Roskin said.
Israel has limited insight into tunneling activities on the Egyptian side of the border, he added. Many of the networks end in northern Sinai, but the Egyptian government has rarely allowed Israeli researchers or government officials to visit the area, so it is not clear how many cross-border tunnels remain.