The World Health Organisation says the situation is desperate at Gaza's Al-Shifa Hospital where Israel has mounted a military operation and in the rest of the Palestinian territory.
Israel accuses Hamas of running a command centre in tunnels under the hospital and the United States says it has intelligence that supports this.
Hamas denies this and says the raid on the hospital is a war crime - hundreds of civilians have been sheltering there, alongside patients and staff.
The boss of Médecins Sans Frontières Australia says the organisation has seen no evidence that it is being used as a military base during decades of work there.
The United Nations Security Council has passed a resolution calling for "extended humanitarian pauses" in Gaza and the release of all hostages.
Dr Margaret Harris from the World Health Organisation said there had been on and off communication with staff at Al-Shifa, but it was extremely difficult.
The communication systems had been getting worse due to lack of power which was due to lack of fuel, she said.
"We were told that 34 of the premature babies are still alive, that means five have died because there were originally 39."
They had managed to bury 82 bodies, but another 80 remain unburied, she said.
"They've got bodies all around in the hospital they haven't been able to bury because of the fighting and because of the attacks on the hospital."
There were kidney patients who desperately needed hemodialysis, which they managed to do for two hours, she said.
"I'm not quite sure how they managed to it, I think it must've been on back-up battery supply. They've got no central oxygen, water or fuel, you know the medical staff are starving - and there are a lot of people still in there."
Inside Al-Shifa Hospital on 10 November, 2023 amid ongoing battles between Israel and Hamas. Photo: Khader Al Zanoun / AFP
There were still 633 patients at the hospital and 116 doctors - but the hospital had a total staff of 500 including the nurses, administrative staff, hygienists, she said.
There was also an initial estimate that another 3000 people were sheltering at the hospital, but a lot of them may have left, she said.
"And it's desperate."
Responding to the Israeli Defence Force's claim that Hamas was in the hospital building and that they want to find the militants, Dr Harris said she was "not there to verify any claims made by either side".
"But a hospital is defined as a safe haven, it's defined as a safe place and international humanitarian law is very very clear on that," she said.
"The principle is that health care facilities should not be attacked or used to commit acts harmful to the enemy."
Dr Harris said there was no independent verification that the hospital was being used for military purposes, but even if this were the case, health care facilities were never without protection.
"Health care is sacrosanct, you do not use it for military purposes, but just because you suspect something might be going on that doesn't mean you can make it a target either."
Elsewhere in Gaza, health conditions were getting worse due to the conditions, she said.
"We've already documented huge outbreaks of diarrhea that normally we would expect to see around 2000 cases in a month, and just in the last couple of weeks we've seen 35-40,000 cases."
There was no functioning sewage system because there was no power, she said.
Torrential rain had also started a day ago, which meant sewage was pouring through the streets, she said.
But the poor communication and chaos in Gaza made it very difficult for health officials to document anything, she said.
For the last four days the health ministry in Gaza has not reported information regarding the number of deaths and injuries because they could not get the information from the hospitals, she said.
"The dead are just lying where they die and likewise the injured can't get to hospital to be counted or treated."
She said a lot of the people who had been displaced had no shelter and so were sleeping in the streets in the pouring rain.
"So you've got all the elements for health catastrophe, which we've already got but now this is a doubling of the disaster."
There hospitals need power and hostilities need to cease in order to help the people who are in a horrific and desperate situation, she said.
Dr Harris said they also wanted Hamas to free the Israeli hostages and to ensure that the hostages received medical care.
"We're pushing at all levels to get help to them and to get them freed."
