RAFAH, Gaza Strip >>Israeli troops and tanks launched a brief ground raid into northern Gaza overnight into Thursday, the military said, striking several militant targets in order to “prepare the battlefield” ahead of a widely expected ground invasion after more than two weeks of devastating air raids.

The raid came after the U.N. warned it is on the verge of running out of fuel in the Gaza Strip, forcing it to sharply curtail relief efforts in the territory, which has also been under a complete siege since Hamas’ bloody rampage across southern Israel ignited the war earlier this month.

The rising death tolls in Gaza are unprecedented in the decades-long Israeli-Palestinian conflict. Even greater loss of life could come if Israel launches an expected ground offensive aimed at crushing Hamas, which has ruled Gaza since 2007 and survived four previous wars with Israel.

The Health Ministry in Hamas-ruled Gaza said Wednesday that more than 750 people were killed over the past 24 hours, higher than the 704 killed the previous day. The Associated Press could not independently verify the death toll, and the ministry does not distinguish between civilians and combatants. By comparison, 2,251 Palestinians, mostly civilians, were killed in the entire six-week-long war in 2014, according to U.N. figures.

On Wednesday, the wife, son and daughter of Wael Dahdouh, a veteran Al-Jazeera correspondent in Gaza, were killed in an Israeli strike. The Qatar-based satellite channel broadcast footage of his grief upon entering a hospital and peering over the body of his dead son.

The Israeli military says it only strikes militant targets and accuses Hamas of operating among civilians in densely-populated Gaza. Palestinian militants have fired rocket barrages into Israel since the war began.

During the overnight raid, the military said soldiers struck fighters, militant infrastructure and anti-tank missile launching positions. There were no immediate reports of casualties on either aide.

Meanwhile, an airstrike hit a residential building in the southern town of Khan Younis early Thursday. Ambulances streamed into the nearby Nasser Hospital, but there was no official word on casualties. Family members said the building had housed 75 people, including 25 displaced relatives.

The Gaza Health Ministry says more than 6,500 Palestinians have been killed in the war. That figure includes the disputed toll from an explosion at a hospital last week.

The fighting has killed more than 1,400 people in Israel, mostly civilians slain during the initial Hamas attack, according to the Israeli government. Hamas also holds some 222 hostages in Gaza.

The warning by the U.N. agency for Palestinian refugees, UNRWA, over depleting fuel supplies raised alarm that the humanitarian crisis could quickly worsen.

Gaza’s population has also been running out of food, water and medicine. About 1.4 million of Gaza’s 2.3 million residents have fled their homes, with nearly half of them crowded into U.N. shelters. Hundreds of thousands remain in northern Gaza, despite Israel ordering them to evacuate to the south, saying those who remain might be considered “accomplices” of Hamas.

In recent days, Israel let more than 60 trucks with aid enter from Egypt, which aid workers say is insufficient and only a tiny fraction of what was being brought in before the war. Israel is still barring deliveries of fuel — needed to power generators — saying it believes Hamas will take it.

An official with the International Committee of the Red Cross said it hopes to bring in nearly a half dozen trucks filled with vital medical supplies.

“This is a small amount of what is required, a drop in the ocean if you will, given the severity of the consequences of the violence in the last two and a half weeks,” said William Schomburg, head of the sub-delegation in Gaza.

“Today, we are looking at eight to ten trucks coming in. We have more that are lined up,” he said. “We are trying to establish a pipeline.”

UNRWA has been sharing its own fuel supplies so that trucks can distribute aid, bakeries can feed people in shelters, water can be desalinated, and hospitals can keep incubators, life support machines and other vital equipment working.

If it continues doing all of that, fuel will run out by Thursday, so the agency is deciding how to ration its supply, UNRWA spokeswoman Tamara Alrifai told The Associated Press.

“Do we give for the incubators or the bakeries?” she said. “It is an excruciating decision.”

More than half of Gaza’s primary health care facilities and roughly a third of its hospitals have stopped functioning, the World Health Organization said.

At Gaza City’s al-Shifa Hospital, the lack of medicine and clean water have led to “alarming” infection rates, the group Doctors Without Borders said. Amputations are often required to prevent infection from spreading in the wounded, it said.

One surgeon with the group described amputating half the foot of a 9-year-old boy with only “slight sedation” on a hallway floor as his mother and sister watched.

The conflict has also threatened to spread across the region. The Israeli military said Wednesday it struck military sites in Syria in response to rocket launches from the country. Syrian state media said eight soldiers were killed and seven wounded.

Strikes in Syria also hit the airports of Aleppo and Damascus, in an apparent attempt to prevent arms shipments from Iran to militant groups, including Lebanon’s Hezbollah. Israel has been exchanging near daily fire with Iranian-backed Hezbollah across the Lebanese border.

Hamas’ surprise rampage on Oct. 7 in southern Israel stunned the country with its brutality, its unprecedented toll and the failure of intelligence agencies to know it was coming. Prime Minister Benjamin Netanyahu said in a speech Wednesday night that he will be held accountable, but only after Hamas was defeated.

“We will get to the bottom of what happened,” he said. “This debacle will be investigated. Everyone will have to give answers, including me.”

Magdy reported from Cairo and Keath from Athens. Associated Press writers Wafaa Shurafa in Deir al-Balah, Gaza Strip; Aamer Madhani in Washington; Amy Teibel in Jerusalem; Edith M. Lederer at the United Nations; Sarah El Deeb in Beirut; and Brian Melley in London contributed.