Hamas has said it will resist any foreign military presence involved with the project and UN officials touring the site on Thursday had to take cover amid a mortar attack.

Some analysts believe the US and others have greater sway over Israel following the Iranian drone, missile and rocket barrage two weeks ago, in which Western forces played a decisive role in intercepting the projectiles.

The attack made clear Israel “relies on Centcom [United States Central Command] for forward cover”, said an Israeli intelligence analyst. It also “reset the diplomatic compass”, with Israel’s “measured response” demonstrating a degree of strategic acumen in the eyes of its partners.

There can be little doubt an attack on Rafah could prove costly diplomatically.

“Rafah has become an international symbol, so perhaps relations are going to be difficult regardless of the changing conditions,” said Brig Gen Assaf Orion.

“The cost depends on the method and prior evacuation and humanitarian support, of which there are early indicators – tents, US dialogue, aid flood, etc.”

Regardless, planning is under way on the ground.

“We are looking at where there are still partially functioning hospitals in the other areas, and [asking] will they be able to manage an upsurge in patients?” said Nyka Alexander, part of the WHO’s health emergencies division.

While the flow of food into the area had improved recently, Ms Alexander said conditions in Rafah were poor, citing a lack of nutritious food, lice, extreme heat and food-borne viruses, including hepatitis.

“There are just so many difficulties that people here face,” she said. “I was at a shelter yesterday, a shelter for 50,000 people. There are 44 toilets. So you do the maths.”