United States president Donald Trump's proposed US$54 billion boost for the military is the country's largest since Ronald Reagan's Pentagon build-up in the 1980s.
The budget plan includes US$1.5 billion allocated for the US-Mexico border wall, despite Mr Trump's campaign promise that Mexico would pay for it.
The spending would be offset by cuts to foreign aid and domestic agencies including health, education and the environment.
Congress must still approve the budget, and politicians such as Democratic House Minority Leader Nancy Pelosi are expressing opposition to many of the proposals.
"The federal budget should be a statement of our national values. What is important to us as a country should be reflected in how we allocate our resources in a budget. This budget is not a statement of values of anyone, but President Trump has shown that he does not value the future of our children and working families. So, it throws billions of dollars at defence while ransacking America's investment in jobs, education, innovation, clean energy and life-saving medical research. It will leave our nation weakened."
If Congress approves it, the US State Department would face a 28 per cent reduction in funding, meaning cuts to foreign aid.
Secretary of State Rex Tillerson says he has accepted more than a quarter of his agency's budget could be cut, describing current spending as not sustainable.
"We are going to be undertaking a very comprehensive examination of how programs are executed, a very comprehensive examination of how we are structured, and I'm confident that, with the input of the men and women of the State Department, we are going to construct a way forward that allows us to be much more effective, much more efficient, and be able to do a lot with fewer dollars."
Some agencies would lose all funding, including the Corporation for Public Broadcasting that funds National Public Radio and the Public Broadcasting Service, or PBS television.
Funding would also disappear completely for 19 independent bodies that count on federal money for the arts and regional programs.
Other proposed reductions and cuts include community-development grants at the Department of Housing and more than 20 Department of Education programs.
The director of the Office of Management and Budget, Mike Mulvaney, says Mr Trump is simply delivering on his promises.
"We wrote a budget based upon his campaign promises, and that's what you see in the budget. We took his words and turned them into numbers."
The Trump administration also says it intends to reduce or end funding for international organisations whose missions do not substantially advance US foreign-policy interests.
Stephane Dujarric, spokesman for the United Nations secretary general, warns any significant cuts would have long-term consequences.
"The point about abrupt funding cuts is, in any reform process, if you are forced to make quick cuts as opposed to things that are planned or phased in and thought through, you hamper the long-term prospects of effective reform."
