Israel-Gaza updates: Gantz rejects Netanyahu's request, resigns

The Hamas military wing claimed in a statement Sunday that three hostages, including an American citizen, were killed in Saturday's rescue operation in central Gaza that was carried out by the Israel Defense Forces.

The IDF told ABC News on Sunday it had no knowledge of hostage deaths occurring during Saturday's raid on the Nuseirat refugee camp, in which four hostages were rescued.

In its statement, Hamas' Al-Qassam Brigades accused the Israeli government of being untruthful about the circumstances of the raid.

"In exchange for them, your own army killed three of your own captives in the same attack; one of them holds an American citizenship," the Al-Qassam Brigades statement said. "Time is running out. Your government is lying."

A White House National Security Council spokesperson said Sunday they have "seen nothing to corroborate" the claims that three other hostages, including an American, were killed during the raid.

"We have seen nothing to corroborate these claims. We are of course continuing to assess the claims," the spokesperson told ABC News.

At least 274 people were killed when the Israeli military moved into the Nuseirat camp to rescue hostages, the Hamas-run Gaza Health Ministry said Sunday. Israel's military said no more than 100 civilians were killed in the operation.

-ABC News' Victoria Beaulé, Jordana Miller and Michelle Stoddart

At least 274 people were killed in central Gaza on Saturday as the Israeli military moved into the Nuseirat camp to rescue four hostages, the Hamas-run Gaza Health Ministry said Sunday.

Another 698 people were injured as Israeli forces entered the refugee camp, the ministry said.

Some of the injured were in critical condition, the ministry said.

The death toll in Gaza climbed on Saturday to 37,084 people, the ministry said. More than 84,000 others have been injured, the ministry said.

-ABC News’ Victoria Beaule and Kevin Shalvey

U.S. Central Command (USCENTCOM) announced Saturday that it began delivery of humanitarian assistance ashore in Gaza.

"Today, a total of approximately 492 metric tons (~1.1 million pounds) of much needed humanitarian assistance was delivered to the people of Gaza," CENTCOM said in a statement.

No U.S. personnel went ashore to Gaza, according to CENTCOM.

The agency said it has so far assisted in the delivery of more than 1,573 metric tons of humanitarian aid to organizations operating on the ground in Gaza.

-ABC News' Nathan Luna

Secretary of State Antony Blinken released a statement Saturday following the rescue of four Israeli hostages, welcoming their safe return.

"The United States will not rest until every hostage is returned home," he said.

Blinken also pushed for the cease-fire announced last week by President Joe Biden.

He contended would "bring relief to both the people of Gaza and the remaining hostages and their families through an immediate ceasefire that could lead to the release of all hostages, a surge of humanitarian assistance, Gaza’s reconstruction, and an enduring end to the war."

"The only thing standing in the way of achieving this ceasefire is Hamas. It is time for them to accept the deal," he said.

A U.S. defense official provided ABC News with some more details about the operation.

The official said the recently constructed JLOTS pier, which is used for transporting humanitarian supplies, was not used in the operation.

"An area south of the facility was used to safely return the hostages to Israel. Any such claim to the contrary is false," the official said.

-ABC News' Nathan Luna