JERUSALEM - Israel's military declared on Tuesday that it has pumped seawater to flood the Hamas underground tunnel network in the Gaza Strip.

It was the first time that the Israel Defense Forces (IDF) officially acknowledged using the controversial strategy, which some United Nations hydrologists and environmental experts warned could destroy the majority of Gaza's drinkable water and harm agriculture.

"During the war, the IDF has implemented new capabilities to neutralize underground terrorist infrastructure in the Gaza Strip by channeling large volumes of water into the tunnels," the IDF said in a statement.

The measure is part of "a range of tools deployed by the IDF" to neutralize the subterranean network of tunnels, it said.

"The capability was developed in a professional capacity, including analysis of the soil characteristics and the water systems in the area to ensure that damage is not done to the area's groundwater. The pumping of water was only carried out in tunnel routes and locations that were suitable, matching the method of operation to each case," it said.

According to Israeli figures, Hamas's tunnels stretch over about 560-725 km beneath the coastal Palestinian enclave. On Sunday, the US paper The Wall Street Journal quoted Israeli and US officials as reporting that some 80 percent of the Hamas tunnel system remains intact.

At least 26,751 Palestinians have been killed and 65,636 others injured in the Gaza Strip since Israel launched its massive offensive on Oct 7, 2023, according to an update issued on Tuesday by the Gaza-based Palestinian Health Ministry.

The Israeli military operation followed a Hamas-led cross-border surprise attack on southern Israeli communities, which killed about 1,200 people.