Gaza faces a catastrophe extending far beyond a humanitarian crisis, the head of medical charity Médecins Sans Frontières (MSF) has said, describing the situation in the densely populated enclave as chaotic.

Israeli forces battled Hamas in the Gaza Strip’s biggest cities on Thursday in a new phase of the war that is now entering its third month, with wide areas of the narrow territory flattened by Israeli bombardment and 85 per cent of the 2.3 million population left homeless, according to UN figures.

“My people on the ground keep updating me on the situation, and I can tell you that it has gone far beyond the humanitarian crisis,” Dr Christos Christou, international president of Doctors Without Borders, told reporters in Geneva.

“It is a humanitarian catastrophe. It is a chaotic situation, and I’m extremely worried that very soon people will be in a mode of just trying to survive, which will come with very severe consequences.”

In a bid to escape Israeli bombardment, Gazans have amassed at the southern tip of Gaza, heeding Israeli leaflets and messages saying that they would be safe on the border with Egypt. The United Nations and aid organisations have said that nowhere is safe in Gaza.

“The people have been asked to be squeezed in a very small area,” Dr Christou said. “My teams on the ground keep saying to me that it is unbearable. It is unsustainable … There is no safe place.”