US President Donald Trump is seeking to boost defence spending by $54bn (£43bn) in his proposed budget plan for 2018, which is about a 10% increase.
The blueprint also calls for deep cuts elsewhere, including to foreign assistance and environmental budgets.
But Mr Trump’s plan leaves large welfare programmes untouched, despite Republican calls for reform.
The president has consulted government agencies of his plans and will present his budget to Congress in May.
“We’re going to do more with less and make the government lean and accountable,” Mr Trump said at the White House.
The president, who vowed to increase military spending and preserve welfare programmes during his campaign, said the budget will focus on “military, safety, economic development”.
“It will include an historic increase in defence spending to rebuild the depleted military of the United States of America at a time we most need it,” he said.
Military spending has declined in recent years due to budgetary battles in Congress that led to spending freeze on defence.
Mr Trump’s proposal would return the US closer to wartime spending.
He also said he would discuss his plans for infrastructure spending, in a speech to Congress on Tuesday. “We’re going to start spending on infrastructure big,” he said.
The Republican did not say how his budget proposal will tackle mandatory spending and taxes, promising those details to come later.
Mr Trump pledged to cut taxes during his presidential campaign, which would likely add to the national debt.
Analysis – Anthony Zurcher, BBC News North America Reporter
Keeping both of his campaign promises – boosting the military and protecting welfare – will put the president in a tough bind.
If he wants to boost the defence budget by $54bn without adding to the deficit, that money will have to come from somewhere – and mandatory spending on welfare and debt interest takes nearly 70% of the budget off the table.
Early reports are that the Environmental Protection Agency is facing sharp cuts, but its total annual budget is just over $8bn -a drop in the bucket.
The State Department has also been singled out as a source for the needed funds, and its $50bn annually (including $22bn in direct aid) makes it a fatter target.
The lion’s share of humanitarian assistance goes to rebuilding efforts in Afghanistan and Aids treatment in Sub-Saharan Africa, however, which will be difficult to touch. Also unlikely to get the axe is military support, dominated by $3.1bn annually to Israel.
There’s a reason the Trump administration announced the military budget number before revealing where the money will come from. Spending is easy; cutting is hard.
The White House sent Mr Trump’s 2018 budget blueprint, which begins on 1 October, to federal agencies on Monday,
The agencies will then review the plan and propose changes to the cuts as the White House prepares for negotiations with Congress.
The Republican-controlled Congress must approve any federal spending.
Mr Trump’s plan is expected to face backlash from Democrats and some Republicans over cuts to domestic programmes.
Congresswoman Nita Lowey, the ranking Democrat on the House Appropriations Committee, said Mr Trump’s plan is harmful to working families.
“Democrats will make crystal clear the misplaced priorities of the Administration and the Republican majority, and we will fight tooth and nail to protect services and investments that are critical to hardworking American families and communities across the country,” she said.
Trump lays out hike in military spending