WATCH: Vought won't say how much Trump has spent on Iran war so far

Russell Vought, director of the Office of Management and Budget, declined to tell lawmakers on the Senate Budget Committee in a hearing Thursday how much the federal government has spent on the Iran war so far.

Watch the clip in the video player above.

"We don't have that figures right now, I think in part because it's fluctuating on a day-in, day-out basis," he told Sen. Patty Murray, D-Wash.

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"You can't even give us a range," Murray said.

Vought said no, prompting Murray to say that Congress has to know how much is being spent so they can put their budgets together and make annual preparations.

"I just find it outrageous that as director you're not willing to tell us what those costs are," she said. "It's your job to know."

Vought, a key figure in the Trump administration's efforts to shrink the federal workforce, also defended the president's budget request in a House hearing Wednesday.

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President Donald Trump's funding wish list for fiscal year 2027 includes a staggering bump for defense spending — a nearly 50% increase to $1.5 trillion — to build his "dream military."

The president's budget request is not final, but it does signal the Trump administration's priorities for the coming fiscal year. Though Trump has tried to exert more authority over spending in his second term, it's up to both chambers to revise and approve the final budget in the coming months.