Live updates: Follow the latest on Israel-Gaza
Doctors at Gaza's Indonesian Hospital have described bodies piled up outside morgues and doorways as Israeli forces surround the complex in Beit Lahia.
The hospital has become a "mass grave", head of the nursing department Essay Nabhan said in a statement shared by Health Ministry officials.
Israeli forces have surrounded the large complex, a major trauma care centre in northern Gaza, after a concentrated and prolonged assault on Al Shifa Hospital.
Gaza's already-fragile healthcare system has buckled under the weight of the six-week war, which has left only nine out of 35 hospitals offering some form of care across the whole enclave.
The Israeli army "want to turn the Indonesian Hospital into military barracks" and is continuing to target the building, Mr Nabhan said.
At least 12 people were killed when the hospital was bombed on Monday, as Israeli tanks and snipers surrounded the area. People at the hospital later reported soldiers shooting at "anything that moves" as civilians and patients huddled inside.
There has been no definitive death toll at the complex since the initial attack.
"The Indonesian Hospital is besieged and anyone who leaves it is at risk," Health Ministry spokesman Mehdat Abbas told The National on Tuesday. "The hospital is the target of indiscriminate bombing and there are no information regarding the fate of patients."
Doctors struggled to manoeuvre around the dead in corridors and have resorted to cooking oil to provide power for the hospital, while others said corpses have piled up outside the hospital mortuaries.
Several hundred people were confirmed to have been evacuated and taken to Al Nasser Hospital in Khan Younis on Monday night.
At least 13,300 people have been killed in Israeli strikes on Gaza since October 7, according to figures from the Health Ministry.
The real figure is likely to be much higher, with at least 6,000 people missing.
"Bodies are on the streets and under rubble ... there is no accurate figure, given the smell of decomposing bodies near all demolished buildings," Mr Abbas said.
"The health sector in Gaza is in a state of complete collapse" and there is a "severe shortage" of medical supplies, the ministry said in an update on Tuesday.
Al Shifa, Al Quds and the Indonesian hospitals in northern Gaza "are all under direct Israeli fire", it added.
"Al Ahli Baptist Hospital is currently the only functioning hospital in Gaza city amid a lack of medical supplies."
On Tuesday, a UN health agency representative said all three hospitals had requested help with evacuations.
'Not enough beds'
Officials from the Indonesian MER-C organisation, which built the hospital, told The National they lost contact with staff there almost two weeks ago.
Doctors said they had no water, food or medicine, said engineer Nur Ikhwan Abadi.
“We can't distribute any food or medicine. Even if we make contact with them, we can't do anything,” he said.
At Al Aqsa Martyrs' Hospital, more than half of the wounded patients are children, spokesman Dr Khalil Al Dakran told The National.
Six thousand injured people, mostly women and children, have arrived at the hospital since start of the war.
Patients are being treated in corridors and outdoor tents, Dr Al Dakran said. "This hospital is the only one providing services for the central Gaza Strip.
"The hospital can’t deal with the huge number of wounded people that have arrived at the hospital due to the shortage of the medical supplies, medicines and fuel.
"There are not enough beds for them."