The figure, accounting for the war’s first two days, is likely to intensify concerns in Congress that U.S. forces are churning through a scarce supply of advanced weaponry. The Pentagon burned through $5.6 billion worth of munitions during the first two days of its military assault on Iran, according to three U.S. officials, a figure that underscores the deepening alarm among some on Capitol Hill over the speed at which U.S. forces have eaten into the scarce supply of America’s most advanced weaponry.The estimate, shared with Congress on Monday, raises new questions about the Trump administration’s broad dismissal of lawmakers’ concerns that the Iran operation is quickly eroding the U.S. military’s readiness.

The Trump administration also is expected to send Congress a supplemental defense budget request as soon as this week — potentially totaling tens of billions of dollars — to help sustain its campaign, officials said. That, too, is expected to face opposition from many Democrats whose attempts to restrain the administration from further military action in Iran have come up empty.The $5.6 billion figure highlights how costly the strikes were before that transition began, said the officials, who like some others spoke on the condition of anonymity to discuss the sensitive estimate. They did not specify how many and what kinds of munitions were expended in the war’s opening days.

The Post has previously reported that the military has fired hundreds of precision weapons since the start of hostilities on Feb. 28, including advanced air defense interceptors and Tomahawk cruise missiles. U.S. Central Command, which oversees military operations throughout the Middle East, has said that more than 5,000 targets have been hit in Iran using more than 2,000 munitions.

Mark Cancian, who closely monitors U.S. inventories at the Center for Strategic and International Studies, said the shift away from these longer-range munitions will dramatically lower the price of each strike — from millions of dollars spent on each round fired to less than $100,000, in some cases.