At Nasser Hospital in southern Gaza, a man cradling a boy with a bloodied scalp cried for help.
Another boy with a gash on his cheek and tears in his eyes lay under a blanket. A third, his face covered in blood, waited for treatment.
Within hours of the lapse of a week-old truce between Israel and the Palestinian group Hamas which runs Gaza, the enclave's health ministry reported that at least 60 people had already been killed in Israeli air strikes.
Reuters footage from Nasser Hospital, the second largest in Gaza, showed a steady stream of wounded being brought in as other people wept outside beside bodies of loved ones killed in strikes.
Aid groups and the United Nations say a small fraction of health facilities in the devastated enclave are still functioning and those are in no shape to handle a new wave of casualties.
"Hospitals across Gaza lack the basic supplies, staff and fuel to deliver primary health care at the scale needed, let alone safely treat urgent cases," UN Secretary-General Antonio Guterres said on Thursday.
Crippled health system
Gaza had 2.3 million residents before Israel began a bombardment and ground invasion in response to the Oct. 7 rampage by Hamas, when Israel says gunmen killed 1,200 people and took 240 hostages.
Palestinian health authorities that the UN deems credible say more than 15,000 Gaza residents have been confirmed killed and thousands more are missing and feared buried under rubble. The UN says as many as 80 percent of the population may have been driven from their homes.
"Gaza's health system has been crippled by the ongoing hostilities," Dr Richard Peeperkorn, the World Health Organization's representative in Gaza, said.
"It cannot afford to lose any more hospitals or hospital beds," he told reporters by video link. "We are extremely concerned about the resumption of violence."