As Israel preps for possible ground invasion, a look at the labyrinth of tunnels in Gaza

Hamas militants are using hundreds of miles of secret tunnels under Gaza and into Israel to attack Israeli targets, move weapons, and, most recently, hold hostages.

Hamas has used the tunnels, estimated between 150 to 300 miles in length, for decades in its war against Israel. The militant group claimed the underground network was 311 miles in 2021, but this has not been independently verified.

The network, consisting of about 1,300 tunnels, will present special problems for Israel Defense Forces members if Israel invades with ground troops. The tunnels are small, with some estimated at about 6-by-6 feet in size. Others are even smaller.

Israel said it launched more than 400 airstrikes into Gaza on Tuesday and 320 on Monday. Some of those strikes targeted tunnels.

Tunnel networks identified by Israeli military

The tunnel network exists in a country that's 140 square miles in size with a population of about 2 million people.

Some of the tunnels are as deep as 100 feet below the surface. One was found about 230 feet deep.

Yocheved Lifshitz, 85, a hostage taken and later released by Hamas, described the tunnels as spiderwebs of wet tunnels. She said hostages walked for two to three hours in tunnels to a hall where other hostages were kept, the Washington Post reported.

How big are Gaza tunnels?

Tunnels allow Hamas operatives to evade aerial surveillance by aircraft and satellites. The militants first used the network to attack Israel in 2001, NBC News said.

The first tunnels were dug in the 1960s for smuggling and more were built as surveillance technology improved.

Hamas took control of Gaza in 2007. It increased tunnel construction and began digging tunnels under the border. Israel discovered the expanded network in 2013 and launched a major attack to destroy it in 2014.

Hamas leaders use parts of the network as command centers to guide military operations, Israeli experts say. The Israeli military says Hamas has used millions of dollars in aid to pay for building the tunnels.

SOURCE USA TODAY Network reporting and research; Associated Press