The health ministry in the Gaza Strip said Friday hospitals have only two days' fuel left before they must restrict services, after the UN warned aid delivery to the war-devastated territory is being crippled.
The warning came a day after the International Criminal Court issued arrest warrants for Israeli Prime Minister Benjamin Netanyahu and former defence minister Yoav Gallant more than a year into the Gaza war.
The United Nations and others have repeatedly decried humanitarian conditions, particularly in northern Gaza where Israel claimed Friday it had killed two Hamas commanders.
Gaza medics said an overnight Israeli raid on Beit Lahia and nearby Jabalia resulted in dozens killed or missing.
Marwan al-Hams, director of Gaza's field hospitals, told reporters all hospitals in the Palestinian territory "will stop working or reduce their services within 48 hours due to the occupation's (Israel's) obstruction of fuel entry".
World Health Organization chief Tedros Adhanom Ghebreyesus said Friday he was "deeply concerned about the safety and well-being of 80 patients, including 8 in the intensive care unit" at Kamal Adwan hospital, one of just two partly operating in northern Gaza.
Kamal Adwan director Hossam Abu Safia told AFP it was "deliberately hit by Israeli shelling for the second day" Friday and that "one doctor and some patients were injured".
Late Thursday, the UN's humanitarian coordinator for the Palestinian territories, Muhannad Hadi, said: "The delivery of critical aid across Gaza, including food, water, fuel and medical supplies, is grinding to a halt."
He said that for more than six weeks Israeli authorities "have been banning commercial imports" while "a surge in armed looting" has targeted aid convoys.
Israel began an air and ground operation in Jabalia on 6 October and then expanded it to Beit Lahia. Gaza's health ministry says the operation has killed thousands.
The UN says more than 100,000 have been displaced from the area, and an official told the Security Council last week that people "are effectively starving".