The Pentagon needs $80 billion to cover costs from the Iran war as well as other non-war-related bills, the Wall Street Journal reported on Thursday, citing people familiar with the matter.
Deputy Defense Secretary Stephen Feinberg told lawmakers of the cost in phone calls earlier this week, according to the report.
A full US supplemental request, which will include money for the Pentagon as well as non-defense priorities such as farm and disaster relief, could be sent to lawmakers in the coming days, it added.
Lawmakers have been pressing the Trump administration to provide a comprehensive figure for the war that is now approaching its 4-month mark.
Certain congresspeople have reportedly expressed concern over the administration's expenses in the months-long campaign against Iran, fueled by the large amount of resources and personnel deployed to the region that might be needed elsewhere around the world, the report added.
The Iran war has cost around $25 billion, a Pentagon official told Reuters in April, providing the first official estimate of war costs.
However, the full cost of the conflict, which Trump began alongside Israel on February 28, has remained an open question on Capitol Hill, and an initial $200 billion request for additional funding met stiff opposition from lawmakers.
White House budget director Russell Vought told a hearing in April of the House of Representatives Budget Committee that he had no estimate for the cost of the war, as he defended Trump's request for a $1.5 trillion annual military budget.
The proposed budget reflects Republican priorities ahead of November’s midterm elections, in which the party is trying to retain control of Congress but faces growing voter anxiety over rising living costs, high energy prices, and the financial burden of the war in Iran.