Jerusalem (AFP) - The United Nations said Thursday it discovered a "man-made cavity" under one of its schools in Gaza, the Palestinian territory controlled by Hamas, which boasts a network of tunnels, some of them used in past wars against Israel.
"The agency protested strongly to the relevant authorities in Gaza to express outrage and condemnation of the presence of such a structure underneath one of its installations," the UN agency for Palestinian refugees (UNRWA) said in a statement.
The "cavity" constituted "a serious violation of the agency's neutrality and a breach of international law," UNRWA said, noting it exposed children and UN staff to "significant security and safety risks".
The Israeli army said the cavity was in fact a tunnel dug by Gaza militants.
"Rain likely created a hole in the ground that revealed the structure of a terrorist tunnel next to an UNRWA school in Gaza," an Israeli military source told AFP on condition of anonymity.
The UN did not disclose the school's location.
There was no immediate comment from Hamas, the Islamist group which controls Gaza and has fought four wars with Israel in the past 15 years.
Since 2007, when Israel imposed a crippling blockade on Gaza following Hamas's seizure of control, an array of tunnels has been dug, a few of them passing under the border with Israel.
During the May 2021 conflict, Israel launched multiple strikes against what it called the "Gaza Metro", a network of tunnels that had allowed fighters to move around without being spotted by Israeli drones and to take Israeli targets by surprise.
Israeli commanders fear militants could use such tunnels to seize Israeli personnel or civilians for use as bargaining chips in prisoner exchanges.
Israel has boosted its forces around the territory, reinforcing a hyper-secure barrier with an underground steel wall it hopes will prevent tunnels reaching into Israeli territory.