The Archbishop of Canterbury has called on Israel to reverse an order for Gaza hospitals to be evacuated.

Archbishop Justin Welby said that hospitals and patients in Gaza "are in grave danger" and must be protected.

He raised concerns about the Anglican-run Ahli Hospital in the north, which was struck by rocket fire on Saturday night, injuring four staff. 

He said that the hospital is running low on medical supplies and that the seriously ill and injured "cannot be safely evacuated".

"They are facing catastrophe," he said. 

The Archbishop continued: "I appeal for the evacuation order on hospitals in northern Gaza to be reversed - and for health facilities, health workers, patients and civilians to be protected.

"The evil and barbaric terror attacks on Israelis by Hamas were a blasphemous outrage. But the civilians of Gaza are not responsible for the crimes of Hamas.

"Please continue to pray for all innocent people, Israeli and Palestinian, who are caught up in the terrible violence in the Holy Land."

The appeal was made as the United Nations warned that Gaza hospitals are running dangerously low on fuel and basic supplies, putting the lives of thousands of patients at risk. 

"Fuel reserves at all hospitals across Gaza are expected to last for about additional 24 hours," the UN's humanitarian office (OCHA) said on Sunday.

"The shutdown of backup generators would place the lives of thousands of patients at risk."

The Rafah border crossing with Egypt was expected to re-open this morning to allow aid into Gaza and foreign nationals to leave.