In a report provided to U.S. congressional committees, President Donald Trump's administration said it used $5.6 billion in munitions during the first two days of strikes against Iran, a source familiar with the information said Tuesday.

Members of Congress, who may soon have to approve additional funding for the war, have expressed concern that the conflict will deplete U.S. military stocks at a time when the defense industry was already struggling to keep up with demand.

Trump met executives from seven defense contractors on Friday as the Pentagon worked to replenish supplies. The administration has not provided a public assessment of the cost of the conflict it launched on Feb. 28 along with ally Israel.

Members of Congress have clamored for more information, including public testimony from officials about issues including how the conflict might affect the U.S. military's readiness to defend the country.

Several congressional aides have said they expect the White House to soon submit a request to Congress for additional funding for the war. Some officials have said the request could be for $50 billion, but others have said that estimate seems low.