The United States has spent a record of at least $17.9 billion on military aid to Israel since the war in Gaza began and led to escalating conflict around the Middle East, according to a report for Brown University’s Costs of War project, released on the anniversary of Hamas’ attacks on Israel.

An additional $4.86 billion has gone into stepped-up U.S. military operations in the region since the Oct. 7, 2023, attacks, researchers said in findings first provided to The Associated Press. That includes the costs of a Navy-led campaign to quell strikes on commercial shipping by Yemen’s Houthis, who are carrying them out in solidarity with the fellow Iranian-backed group Hamas.

The report — completed before Israel opened a second front, this one against Iranian-backed Hezbollah militants in Lebanon, in late September — is one of the first tallies of estimated U.S. costs as the Biden administration backs Israel in its conflicts in Gaza and Lebanon and seeks to contain hostilities by Iran-allied armed groups in the region.