Will Israel use seawater to flood the labyrinth of tunnels beneath Gaza?

Israel could pump thousands of gallons of seawater into the labyrinthine network of tunnels underneath Gaza in a bid to flush out Hamas fighters, a military expert says.

The potential to flood the tunnels, which the Wall Street Journal (WSJ) reports the Israeli military is considering, would be a significant move and would come with steep risks.

"Yes it can be done, and yes it would work", military analyst Professor Michael Clarke tells Sky News.

Follow latest: Israel responds to US warning about war

Considerable attention has been paid to the use - and alleged use - of Gaza's tunnels during the Israel-Hamas war, following the 7 October attacks.

They are believed to extend for possibly hundreds of miles and exist 30m (100ft) below the surface, making them difficult to map and posing a challenge for any Israeli offensive or potential occupation.

According to the WSJ, in November Israel's army completed the set-up of at least five pumps about a mile north of the al Shati refugee camp that could move thousands of cubic metres of water per hour, flooding the tunnels within weeks.

It was not clear whether Israel would consider using the pumps before all hostages were released, according to the WSJ story.

Hamas has previously said it has hidden captives in "safe places and tunnels".

This is one of two big risks Israel would face if it decided to flood the tunnels, Professor Clarke said.

"They do not know whether or not hostages are being held down there," he said.

Read more:
What lies beneath al Shifa hospital?
Traders 'told of attack on Israel in advance'
British teenager killed in Gaza

The other risk, Professor Clarke said, was that by flooding the tunnels the Israeli military could end up polluting the aquifers that assist with Gaza's water supply.

"That would be a piece of environmental vandalism which the world would not thank Israel for," he added.

However, another possibility is that Israel does not necessarily intend to flood the tunnels at all, at least in the short term.

"Letting a story get out may be a piece of psychological warfare so that it gets any Gazans in the tunnels to get out," Professor Clark suggested.

"To flush them out of the tunnels with words rather than with water."