Israeli military vehicles advanced on Monday to the gates of the besieged Al-Shifa hospital complex, Gazan health officials said, as medical staff detailed the increasingly calamitous conditions inside a facility where fuel, medicine and food are running out for the hundreds of patients and thousands of people sheltering there.

Without electricity or fuel, dozens of corpses are decomposing at the hospital because there is no way to preserve or remove them, a chief nurse and a health official said. And doctors said they were desperately trying to keep premature babies warm after removing them from incubators that were now useless.

Doctors and Gazan health officials have said for days that patients at Al-Shifa were dying because of power at the hospital, the Gaza Strip’s largest. The UN High Commissioner for Human Rights said on Monday that the power cut had led to at least 12 deaths.

Jihan Miqdad, a chief nurse in the emergency room at Al-Shifa, said in a phone interview on Monday that patients who were on life support in the intensive care unit were dying because there was little oxygen.

“The situation here is catastrophic in every sense of the word,” she said.

The Israeli military did not address specific questions about its actions around the hospital. It is “engaged in an intense battle against Hamas,” it said in a statement, adding, “This currently includes the area surrounding the Shifa hospital but not the hospital itself.”

The hospital and other medical centres in Gaza City have been struggling for weeks to maintain operations as Israeli forces closed in and as supplies of fuel and medicine dwindled. The head of the WHO warned on Sunday that Al-Shifa was “not functioning as a hospital anymore” and was struggling to provide care after three days “without electricity, without water and with very poor Internet”.

Israeli officials say Hamas uses hospitals in Gaza, including Al-Shifa, as shields for its fighters, including using vast tunnel networks beneath the hospitals. Hamas has denied the allegations.

On Monday, Israeli military vehicles reached a gate on the eastern side of the Al-Shifa complex, where the maternity hospital is, the Gazan health ministry said. Israeli troops have reached at least two other hospitals in northern Gaza, stepping up their push to empty the facilities, according to Israeli military officials, as fighting around them intensifies.

Al-Shifa was “in the circle of death”, said the health ministry, part of the Hamas-run government of the territory.

Miqdad, the nurse, said that for the staff to remove bodies from the hospital, they need to contact the Red Cross to coordinate with the Israeli military, but the Red Cross has not been responsive.

“No one is asking about us,” she said. “The bodies are decomposing inside the hospital.”

The International Committee of the Red Cross said in a statement that it was “constantly in touch” with the health ministry and other parties, and that “evacuating a hospital amid intense fighting is an extremely complex and risky operation.” It did not respond to a specific question about the bodies.

A spokesman for the Gazan health ministry, Dr ​​Medhat Abbas, said in a phone interview that more than 100 bodies were lying in the hospital’s front yard, another 50 were inside and about 60 others were in the morgue.

Staff members and some 8,000 displaced people sheltering at the hospital are suffering from thirst and hunger, Dr Abbas said. Medical teams are surviving on biscuits and dates, he added.

Dr Nasser Bolbol, the head of the neonatal intensive care unit at Al-Shifa, said in a phone interview that three premature babies had died after what he characterized as an Israeli attack disabled the equipment that provides the department with oxygen. His claim that Israel was responsible could not be independently verified.

Hospital staff members moved the 36 remaining premature babies to the only other department that still had oxygen, but that department lacks the incubators the babies need, he said, adding: “Their lives are in danger.”

Dr Abbas said that medical staff had put sheets of reflective foil and blankets over hospital beds and laid the babies close to one another to simulate as much as possible the warmth of an incubator. He said four of the premature babies at Al-Shifa were born in emergency C-sections after their mothers were killed in strikes.

“Now they have to make it without their mothers and without electricity or special care,” he added.

Dr Bolbol said the neonatal unit had enough baby formula to last another two or three days.

He added that the Red Cross was negotiating with Israeli authorities to evacuate the babies, but that no agreement had been reached so far.

“It’s catastrophic,” Dr. Bolbol said. “I’m watching patients die in front of my eyes and I can’t provide them the slightest bit of help.”