During the 2014 Gaza war, the IDF destroyed 32 tunnels built by Hamas in order to stage attacks within Israel; Hamas also possesses an entire network of tunnels that can be used by its troops in the event of an Israeli attack, and hundreds of smuggling tunnels are said to connect Gaza to Egypt despite Cairo’s efforts to destroy them. Dan Feferman describes what Israel can do to defend itself:
Israel is left with a tough choice—strike now [to destroy tunnels] and almost certainly spark another war, or wait till Hamas strikes and risk a civilian massacre in one of the Israeli villages near Gaza. . . . But Israel does have a number of options, and they tend to go together.
First, Israel must continue and increase its intelligence efforts. This means aggressively gathering intelligence on tunnels that cross into Israel and taking limited action, as much as is possible, to neutralize them. . . . In any case, a clear picture of tunnel locations will be crucial should Hamas launch another war.
Second, U.S.-Israel cooperation on anti-tunnel technology is crucial and will eventually provide a solution. This clearly benefits Israel, but will also aid the U.S. It ensures that Israel can defend itself against threats, thus staving off the next round of fighting. And by researching, developing, and field-testing new technologies in Israel, the U.S. can then deploy these same technologies on its own southern border, and help defend foreign bases and embassies from infiltration abroad.