“Hamas terrorists are hiding in Gaza City inside tunnels underneath houses and inside buildings populated with innocent Gazan civilians,” the military said in a statement on Friday.

Dr Daphne Richemond-Barak is an associate professor in counter-terrorism at Reichman University in Israel. In her 2017 bookUnderground Warfare,Richemond-Barak explored underground warfare through history – from the Vietcong’s Cu Chi tunnels during the Vietnam War to Islamic State’s use of booby-trapped tunnels beneath Mosul in Iraq.

In subterranean Gaza,Richemond-Barak described Hamas militants beneath the Al-Shifa Hospital in Gaza City,enjoying “the highest level of protection available under the laws of war”.

“It affords Hamas operatives a shield against Israeli strikes,as well as a unique opportunity to operate far from surveillance drones,GPS,and other intelligence-gathering technology,” she wrote.

Richemond-Barak says burrowing under densely populated urban areas rendered the tunnels “virtually legally immune” to counterattacks.

“In Gaza,tunnels are dug in civilian homes,pass under entire neighbourhoods,and lead into populated areas inside Israel. This enables Hamas to conceal entry and exit points,and facilitates undetected movement and activity.”

The IDF has previously estimated the construction of one Hamas tunnel would cost about $3 million and require 350 truckloads of building supplies. Israel launched a major operation in 2014 attempting to destroy the tunnel network in 2014,and in 2021 said it destroyed more than 100 kilometres of tunnels beneath Gaza.

Joseph Shelzi,an analyst at New York-based intelligence and security consultancy the Soufan Group,said Israeli ground forces would need to apply a methodical process to eliminate the threat posed by tunnel network,using assault teams,engineers and intelligence support.

Shelzi said that while the IDF would have planned and trained for a mission like this,there was no end to the challenges of subterranean warfare.

“Tunnel collapse is a real concern when things start exploding underground,as well as booby traps and mines which will pose hazards and delay advances,” he said.

“Operating in such a restricted environment will also limit soldiers’ ability to see and communicate with one another and will certainly place a psychological strain on those tasked with clearing the dark and confined underground spaces.”

Johns Hopkins University professor of political science Adria Lawrence said that militant organisations were typically better able to protect their members because they had experience operating clandestinely.

“Hamas literally can hide beneath the surface,in these tunnels ... ironically,then,the targets of violence are more likely to escape than innocent bystanders are,” she said.

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