The United States under the Biden and Trump administrations has provided at least $21.7 billion in military assistance to Israel since the start of the Gaza war two years ago, according to a new academic study published Tuesday, the second anniversary of the Oct. 7, 2023, Hamas attacks in Israel that provoked the conflict.

Another study, also published by the Costs of War project at Brown University's Watson School of International and Public Affairs, says the U.S. has spent roughly $10 billion more on security aid and operations in the broader Middle East in the past two years.

While the reports rely on open source material for most of their findings, they offer some of the most comprehensive accountings of U.S. military aid to close ally Israel and estimated costs of direct American military involvement in the Middle East.

The State Department had no immediate comment about the amount of military aid provided to Israel since October 2023. The White House referred questions to the Pentagon, which oversees only a portion of the assistance.

The reports, which draw on publicly available notifications to Congress, were released as President Donald Trump presses for an end to the war in Gaza. Israeli and Hamas officials launched indirect talks in Egypt this week after Hamas accepted some elements of the U.S. plan that Israel also said it supported.

The reports, which are sharply critical of Israel, say that without the U.S. assistance, Israel would not have been able to sustain its concerted campaign against Hamas in Gaza. They note that tens of billions of dollars in future funding for Israel is projected under various bilateral agreements.

The main report says the U.S. provided $17.9 billion to Israel in the first year of the war — when Democratic President Joe Biden was in office — and $3.8 billion in the second year. Some of the military assistance has already been delivered while the remainder will be supplied in the coming years, it said.

That report was produced in conjunction with the Washington-based Quincy Institute for Responsible Statecraft. The institute has been accused by some pro-Israel groups of being isolationist and anti-Israel, charges the organization denies.

A second report analyzing U.S. spending on broader Middle East activities, such as strikes on Yemen's Houthi rebels and Iranian nuclear facilities, puts those costs at between $9.65 billion and $12 billion since Oct. 7, 2023, including between $2 billion and $2.25 billion for the attacks in Iran and associated costs in June.