Israel’s military has begun pumping seawater into the tunnel network allegedly used by the Palestinian group, Hamas, in Gaza, according to a report that was published Tuesday.

The Wall Street Journal, citing US officials briefed on Israeli military operations, said the move to flood the tunnels with water from the Mediterranean Sea is part of a broader strategy employed by Israel to destroy the tunnels.

The effort is reportedly in its infancy stage.

The tunnel system extends for 300 miles and the use of thick blast doors is being assessed by the Israelis, according to US officials.

Initiating the flooding, a process expected to span several weeks, began concurrently with Israel’s installation of two additional pumps to supplement the five pumps added in the previous month.

Preliminary tests were conducted last month, said the US officials.

The move, which was first announced by the newspaper earlier this month, has drawn criticism, with some saying it would create an environmental catastrophe and worsen the situation with fresh water in Gaza.

Several officials from the Biden administration have voiced concern and said using seawater might not be effective and could endanger Gaza’s freshwater supply, according to the report.

Israel believes the underground system has been key to Hamas operations on the battlefield.

Israel has bombarded the Gaza Strip from the air and land, imposed a siege and mounted a ground offensive in retaliation for a cross-border attack by Hamas on Oct. 7.

At least 18,412 Palestinians have been killed and 50,100 injured in the Israeli onslaught since then, according to Gaza’s health authorities.

The Israeli death toll in the Hamas attack stands at 1,200, while nearly 139 hostages remain in captivity, according to official figures.