The head of the Kamal Adwan hospital in Beit Lahiya, Husam Abu Safiya, told Reuters via text message that obeying the order to shut down was "next to impossible" because there were not enough ambulances to get patients out.
"We currently have nearly 400 civilians inside the hospital, including babies in the neonatal unit, whose lives depend on oxygen and incubators. We cannot evacuate these patients safely without assistance, equipment, and time," said Abu Safiya.
"We are sending this message under heavy bombardment and direct targeting of the fuel tanks, which if hit will cause a large explosion and mass casualties of the civilians inside."
The Israeli military did not respond to a request for comment on Abu Safiya's remarks.
Israeli military strikes across the Gaza Strip killed at least 24 Palestinians including children. (AP PHOTO)
On Friday it said it had sent fuel and food supplies to the hospital and helped evacuate more than 100 patients and caregivers to other Gaza hospitals, some in coordination with the Red Cross.
The hospital is one of the only ones still partially functioning in the once crowded northern edge of Gaza, an area under intense Israeli military pressure for nearly three months in one of the most punishing operations of the 14-month-old war.
Abu Safiya said the military had ordered patients and staff to be evacuated to another hospital where conditions are even worse.
Photos from inside the hospital showed patients on beds crammed into corridors to keep them away from windows.
Reuters could not immediately verify those images.
Israel says its operation around three communities on the northern edge of the Gaza Strip - Beit Lahiya, Beit Hanoun and Jabalia - is targeting Hamas militants.
Palestinians accuse Israel of seeking to permanently depopulate the area to create a buffer zone, which Israel denies.
The Israeli military said on Sunday forces operating in Beit Hanoun struck Hamas militants and infrastructure.
The armed wings of Hamas and the allied Islamic Jihad group said they killed many Israeli soldiers.
Elsewhere, Israeli military strikes across the Gaza Strip killed at least 24 Palestinians, including some children, at a school sheltering displaced families in Gaza City, medics said.
The Israeli military said in a statement that the strike targeted Hamas militants operating from a command centre embedded inside the school.
It said fighters used the place to plan and execute attacks against Israeli forces. Hamas denies its forces operate among civilians.
Medics said four Palestinians were killed when an air strike hit a car elsewhere in Gaza City.
An Israeli security official said troops had "struck a Hamas terrorist in a vehicle".
At least 12 other Palestinians were killed in air strikes in Rafah and Khan Younis in the south of the enclave, and Nusseirat and Bureij in the central Gaza Strip, medics said.
Mediators have stepped up efforts in recent weeks to secure a ceasefire in Gaza after months when talks were frozen.
Sources close to the discussions told Reuters on Thursday that Qatar and Egypt had been able to resolve some differences between the warring parties but sticking points remained.
Israel began its assault on Gaza after Hamas-led fighters attacked Israeli communities on October 7, 2023, killing 1200 people and taking more than 250 hostages, according to Israeli tallies.
Israel says about 100 hostages are still being held, but it is unclear how many are alive.
Authorities in Gaza say Israel's campaign has killed more than 45,200 Palestinians.
Most of the population of 2.3 million has been displaced and much of the coastal enclave is in ruins.
