WASHINGTON — The Biden administration said Friday that Israel’s use of U.S.-provided weapons in Gaza likely violated international humanitarian law but wartime conditions prevented U.S. officials from determining that for certain in specific airstrikes.

The administration’s finding of “reasonable” evidence to conclude that its ally had breached international law in its conduct of the war in Gaza, released in a summary of a report delivered Friday to Congress, represents the strongest such statement from Biden officials.

But its caveat that it was unable to link specific U.S. weapons to individual strikes by Israeli forces in Gaza could give the administration leeway in any future decision on whether to restrict U.S. provisions of offensive weapons to Israel.

The administration’s findings, a first-of-its-kind assessment that was compelled by President Joe Biden’s fellow Democrats in Congress, comes after seven months of airstrikes, ground fighting and aid restrictions that have claimed the lives of nearly 35,000 Palestinians, mostly women and children.

Biden has tried to walk a fine line in his support of Prime Minister Benjamin Netanyahu’s war against Hamas. Biden has faced growing rancor at home and abroad over the soaring Palestinian death toll and the onset of famine. Tensions have been heightened further in recent weeks by Netanyahu’s pledge to expand the Israeli military’s offensive in the crowded southern city of Rafah, despite Biden’s opposition.

Biden faces demands from many Democrats that he cut the flow of offensive weapons to Israel and denunciation from Republicans who accuse him of wavering on support for Israel at its time of need.

The Democratic administration took one of the first steps toward conditioning military aid to Israel in recent days when it paused a shipment of 3,500 bombs out of concern over Israel’s threatened offensive on Rafah, a senior administration official said.

The presidential directive, agreed to in February, obligated the Defense and State departments to conduct “an assessment of any credible reports or allegations that such defense articles and, as appropriate, defense services, have been used in a manner not consistent with international law, including international humanitarian law.”

The agreement also obligated them to tell Congress whether they deemed that Israel has acted to “arbitrarily to deny, restrict, or otherwise impede, directly or indirectly,” delivery of any U.S.- supported humanitarian aid into Gaza for starving civilians there.