WASHINGTON, Feb 27 (Reuters) - U.S. President Donald Trump said on Monday he is seeking a “historic increase” in military spending to be funded by cuts elsewhere in government.

Trump will seek to boost Pentagon spending by $54 billion in his first budget proposal and slash the same amount from non-defense spending, including a large reduction in foreign aid, a White House budget official said.

“This budget will be a public safety and national security budget,” Trump told state governors at the White House. “It will include an historic increase in defense spending to rebuild the depleted military of the United States of America at a time we most need it,” he said.

The U.S. military is already the world’s most powerful fighting force and the United States spends far more than any other country on defense.

The White House will send Trump’s proposal to federal departments on Monday as he gears up for budget negotiations with Congress that often take months to play out. Congress, controlled by Trump’s fellow Republicans, has the final say on federal spending.

In a speech to conservative activists on Friday, Trump promised “one of the greatest military buildups in American history.”

Two officials familiar with Trump’s proposal said the planned defense spending increase would be financed partly by cuts to the State Department, Environmental Protection Agency and other non-defense programs.

One of the officials said Trump’s request for the Pentagon included more money for shipbuilding, military aircraft and establishing “a more robust presence in key international waterways and chokepoints” such as the Strait of Hormuz and South China Sea.

A second official said the State Department’s budget could be cut by as much as 30 percent, which would force a major restructuring of the department and elimination of programs.

Some defense experts have questioned the need for a large increase in U.S. military spending, which already stands at roughly $600 billion annually. By contrast, the United States spends about $50 billion annually on the State Department and foreign assistance.

Trump also said he would talk about his plans for infrastructure spending in a speech to Congress on Tuesday. “We’re going to start spending on infrastructure big,” he said.

Treasury Secretary Steven Mnuchin, speaking on Fox News on Sunday, said Trump’s budget would not seek cuts in federal social programs such as Social Security and Medicare.

(Additional reporting by Tim Ahmann and David Alexander; Writing by Alistair Bell; Editing by Frances Kerry)