The United States gathered intelligence last year that Israel’s military lawyers warned there was evidence that could support war crimes charges against Tel Aviv for its military operations in Gaza reliant on American-supplied weapons, five former US officials said.

The previously unreported intelligence, described by the former officials as among the most startling shared with top US policymakers during the war, pointed to doubts within the Israeli military about the legality of its tactics that contrasted sharply with Israel’s public stance defending its actions.

Two of the former US officials said the material was not broadly circulated within the government until late in the Biden administration, when it was disseminated more widely ahead of a congressional briefing in December 2024.

The intelligence deepened concerns in Washington over Israel’s conduct in a war it said was necessary to eliminate Hamas fighters embedded in civilian infrastructure. There were concerns Israel was intentionally targeting civilians and humanitarian workers, a potential war crime which Israel has strongly denied.

US officials expressed alarm at the findings, particularly as the mounting civilian death toll in Gaza raised concerns that Israel’s operations might breach international legal standards on acceptable collateral damage.

The former US officials Reuters spoke to did not provide details on what evidence, such as specific wartime incidents, had caused concerns among Israel’s military lawyers.

Israel has killed more than 68,000 Palestinians during a two-year military campaign, say Gaza health officials. Israel’s military has said at least 20,000 of the fatalities were combatants.

Reuters spoke to nine former US officials in then-president Joe Biden’s administration, including six who had direct knowledge of the intelligence and the subsequent debate within the US government. All spoke on the condition of anonymity because of the sensitivity of the matter.

Reports of internal US government dissent over Israel’s Gaza campaign emerged during Biden’s presidency. This account, based on detailed recollections from those involved, offers a fuller picture of the debate’s intensity in the administration’s final weeks, which ended with President Donald Trump’s inauguration in January.

Israeli Ambassador to the US, Yechiel Leiter, declined to comment when asked for a response about the US intelligence and the internal Biden administration debate about it.

Neither the Israeli prime minister’s office nor the Israeli military spokesperson immediately responded to requests for comment.

Debate intensified in final days of Biden term

The intelligence prompted an interagency meeting at the National Security Council (NSC), where officials and lawyers debated how and whether to respond to the new findings.

A US finding that Israel was committing war crimes would have required, under US law, blocking future arms shipments and ending intelligence sharing with Israel.

Israel’s intelligence services have worked closely with the US for decades and provide critical information, in particular, about events occurring in the Middle East.

Biden administration conversations in December included officials from across the government, including the State Department, the Pentagon, the intelligence community and the White House. Biden was also briefed on the matter by his national security advisers.

The White House did not immediately respond to a request for comment.

“We do not comment on intelligence matters,” a State Department spokesperson said in response to emailed questions about Reuters reporting.

The American debate about whether the Israelis had committed war crimes in Gaza ended when lawyers from across the US government determined that it was still legal for the US to continue supporting Israel with weapons and intelligence because the US had not gathered its own evidence that Israel was violating the law of armed conflict, according to three former US officials.

They reasoned that the intelligence and evidence gathered by the US itself did not prove the Israelis had intentionally killed civilians and humanitarians or blocked aid, a key factor in legal liability.

Some senior Biden administration officials feared that a formal US finding of Israeli war crimes would force Washington to cut off arms and intelligence support — a move they worried could embolden Hamas, delay ceasefire negotiations, and shift the political narrative in favour of the group.

Hamas killed 1,200 people and abducted 251 in its October 7, 2023 attack, with Israel launching its campaign in retaliation.

The decision to stay the course exasperated some of those involved who believed that the Biden administration should have been more forceful in calling out Israel’s alleged abuses and the US role in enabling them, said former US officials.

President Trump and his officials were briefed by Biden’s team on the intelligence but showed little interest in the subject after they took over in January and began siding more powerfully with the Israelis, said the officials.

State Department lawyers repeatedly raised concerns

Even before the US gathered war crimes intelligence from within the Israeli military, some lawyers at the State Department, which oversees legal assessments of foreign military conduct, repeatedly raised concerns with US Secretary of State Antony Blinken that Israel might be committing war crimes, according to five former US officials.

As early as December 2023, lawyers from the State Department’s legal bureau told Blinken in meetings that they believed Israel’s military conduct in Gaza likely amounted to violations of international humanitarian law and potentially war crimes, two of the US officials said.

But they never made a conclusive assessment that Israel was violating international humanitarian law, a move that other US officials at the State Department saw as the legal bureau pulling its punches.

“They saw their job as being justifying a political decision,” one of the former US officials said. “Even when the evidence clearly pointed to war crimes, the Get-Out-Of-Jail-Free card was proving intent,” one of the officials said.

The lack of a definitive conclusion by the State Department’s lawyers was largely reflected in a US government report produced during the Biden administration in May 2024, when Washington said Tel Aviv might have violated international humanitarian law using US-supplied weapons during its military operation in Gaza.

The report, which was prepared by the State Department, stopped short of a definitive assessment, citing the fog of war.

“What I can say is that the Biden administration constantly reviewed Israel’s adherence to the laws of armed conflict, as well as the requirements of our own laws,” Blinken said through a spokesperson for this story. Blinken declined to comment on the intelligence matters.

International concerns about possible war crimes

Last November, the International Criminal Court in The Hague issued arrest warrants for Israeli Prime Minister Benjamin Netanyahu and his former defence chief, as well as Hamas leader Mohammed Deif, for alleged war crimes and crimes against humanity in the Gaza conflict.

Hamas has since confirmed Israel killed Deif.

Israel has rejected the jurisdiction of the Hague-based court and denies war crimes in Gaza. Hamas leaders have dismissed allegations that they committed war crimes.

Among the issues debated by US officials in the final weeks of the Biden administration was whether the government would be complicit if Israeli officials were to face charges in an international tribunal, said people familiar with this debate.

US officials publicly defended Israel but also privately debated the issue in light of
intelligence reports, and they became a point of political vulnerability for Democrats. Biden and later Vice President Kamala Harris waged ultimately unsuccessful presidential campaigns.

Biden did not respond to a request for comment.

Israel, which is fighting a genocide case at the International Court of Justice, rejects genocide allegations as politically motivated and says that its military campaign targets Hamas, not Gaza’s civilian population.

The Israeli military says it seeks to minimise civilian harm while targeting militants embedded in hospitals, schools and shelters, using warnings and appropriate munitions.

An Israeli military official told Reuters in September that the military was investigating about 2,000 incidents of possible misconduct, including civilian deaths and damage to infrastructure.

Some cases came to light through the genocide case filed at the International Court of Justice, the official said.