Administration officials, speaking on condition of anonymity at the White House's insistence, spoke about the bid to boost military spending by about 10 percent on Monday, the same day that Trump promised a "historic" increase in the defense budget.
"This budget follows through on my promise on keeping Americans safe ... It will include a historic increase in budget spending," Trump said as he met state governors at the White House.
The Pentagon's budget increase would fulfill a Trump campaign promise to build up the military.
A senior budget office official said there will be a large reduction in foreign aid and that most domestic agencies will have to absorb cuts, without offering more details.