UN spokesman Stéphane Dujarric said 75,000 litres of fuel were delivered on Wednesday to war-shattered Gaza Strip, home to hundreds of thousands of people in urgent need of humanitarian aid.
However, he stressed that the quantity falls far short of what is required.
"The amount entered yesterday isn't sufficient to cover even one day of energy requirements," Dujarric said on Thursday in New York.
The fuel is critical for powering generators at hospitals, bakeries and other essential facilities in the enclave which remains under an Israeli blockade.
Dujarric warned of the consequences of continued shortages, noting: "One partner, for instance, reported to us this week that, in a matter of days, fuel shortages could cut off supplies to clean drinking water to about 44,000 children that depend on that water source," he said.
Meanwhile, renewed Israeli air strikes across the Gaza Strip killed at least 55 people on Thursday, according to reports in the Hamas-run territory, citing medical sources.
The figures could not be independently verified.
The Palestinian news agency WAFA reported that Israeli strikes targeted multiple areas, including near a medical centre in the city of Deir al-Balah, where 16 people were reportedly killed, with 10 children among them.
Reuters-verified video footage from the strike showed the bodies of women and children lying in pools of blood amid dust and screaming.
One clip showed several motionless children lying on a donkey cart.
"She didn't do anything, she was innocent, I swear. Her dream was for the war to end and that they announce it today, to go back to school," said Samah al-Nouri, sitting by the body of her daughter who was killed in the blast.
"She was only getting treatment in a medical facility. Why did they kill them?" she said, with other bodies laid out around her at a nearby hospital.
Hospital officials said the victims had been waiting for food aid.
The UN children's agency UNICEF confirmed the aid, which was being provided by a partner organisation, had been intended for children and condemned the deaths.
"The killing of families trying to access life-saving aid is unconscionable," UNICEF executive director Catherine Russell said.
She urged Israel to conduct an independent investigation.
"This is the cruel reality confronting many in Gaza today after months of insufficient aid being allowed into the territory, and parties to the conflict failing to uphold basic responsibilities to protect civilians," she said in a statement.
According to UNICEF, a mother waiting in line was severely injured in the Deir al-Balah explosion, and her one-year-old son was killed.
Israel's military said it had targeted a Hamas operative in the area who was involved in the group's October 7, 2023 massacre in Israel.
"The incident is currently under review," the army said, adding that it regrets "any harm caused to uninvolved individuals" and seeks to minimise civilian suffering.
WAFA also reported deadly strikes in Khan Younis in the south and Gaza City in the north.
with Reuters
