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

At least 40 people were killed -- 14 of whom were children -- and at least 74 others were injured in the Israeli strike on an UNRWA school at the Nuseirat Refugee Camp, the Gaza Ministry of Health said Thursday.

Israeli officials have claimed that the strike was targeting Hamas and Islamic Jihad terrorists "hiding inside the school," IDF spokesman Daniel Hagari said during a press briefing Thursday.

The U.S. State Department said Israelis have claimed they were targeting "only one part of the building without hitting areas where civilians were sheltering," spokesperson Matt Miller said Thursday.

"At the same time, we've seen the reports on the ground. We’ve seen the videos on the ground. We've seen the claims that 14 children were killed in the strike and certainly if ... it is accurate that 14 children were killed, those aren’t terrorists. And so the government of Israel has said that they're going to release more information about this strike, including the names of those who died in it," Miller said. "We expect them to be fully transparent in making that information public."

U.N. Secretary-General Antonio Guterres condemned the strike on the school, which the U.N. said was sheltering some 6,000 internally displaced persons, in a statement.

A spokesperson for Guterres said, "He underscores that UN premises are inviolable, including during armed conflict and must be protected by all parties at all times. The Secretary-General calls on all parties to respect and protect civilians, and ensure their essential needs are met, in accordance with international humanitarian law."

-ABC News' Sami Zayara, Jordana Miller and Shannon Crawford

A weapon used in a strike on a UNRWA school sheltering displaced people on June 6 appears to be U.S.-made, three munitions experts told ABC News.

Journalist Emad Abu Shawiesh captured video of weapons fragments at the UNRWA al Sardi school building in Nuseirat in Gaza on June 6.

The weapon fragments seen in the video are consistent with the nose section of a U.S.-made GBU-39 "Small Diameter Bomb," Trevor Ball, a former U.S. Army explosive ordinance disposal specialist, told ABC News.

The GBU-39 also appeared to have been employed in a deadly strike on May 26 in Rafah, Gaza, according to Ball and another munitions expert, who asked not to be named due to the sensitivity of the issue.

Mark Hiznay, an associate director with the Crisis, Conflict and Arms Division of Human Rights Watch, told ABC News the image shows the remnants of a GBU-39.

N.R. Jenzen-Jones, a director at the consultancy Armament Research Services, said the image was consistent with the Small Diameter Bomb series.

“Given what we know about the IDF arsenal and munitions used in previous strikes, the remnants are most likely from a GBU-39 SDB and include a portion of the nose (forward section) of the bomb,” Jenzen-Jones said, adding that other munitions could have been used in the strike, which he had not yet assessed in detail.

-ABC News Chris Looft

The U.S. State Department has sanctioned a militant Palestinian group operating in the West Bank known as "Lions’ Den," it announced Thursday.

The department said the group claimed responsibility for several drive-by shootings around Nablus in 2022, injured and killed Palestinian civilians during clashes with Palestinian Authority Security forces that same year, and that its fighters reportedly targeted Israeli forces at a checkpoint this past April.

The Lions’ Den was the target of an Israeli raid in February. The group has been blamed for much of the surging violence in the West Bank during recent months.

"The United States condemns any and all acts of violence committed in the West Bank, whoever the perpetrators, and we will use the tools at our disposal to expose and hold accountable those who threaten peace and stability there," State Department spokesperson Matt Miller said.

The Biden administration has also imposed a number of sanctions on Israeli West Bank settlers earlier this year; targets include organizations accused of fundraising for extremist settlers and allies of Israel’s far-right National Security Minister Itamar Ben-Gvir.

-ABC News' Shannon Crawford

The United States and 16 other countries released a joint statement this morning calling on Hamas to accept a cease-fire proposal and hostage release deal outlined by President Joe Biden.

"We note that this agreement would lead to an immediate ceasefire and rehabilitation of Gaza together with security assurances for Israelis, and Palestinians, and opportunities for a more enduring long-term peace and a two-state solution," the joint statement said.

The statement was issued by leaders of the United States, Argentina, Austria, Brazil, Bulgaria, Canada, Colombia, Denmark, France, Germany, Poland, Portugal, Romania, Serbia, Spain, Thailand and the United Kingdom.

-ABC News' Justin Gomez and Kevin Shalvey