President Donald Trump has proposed boosting defence spending to USD 1.5 trillion in his 2027 budget released last week, the largest such request in decades, reflecting his emphasis on US military investments over domestic programmes.

The sizable increase for the Pentagon had been telegraphed by the Republican President even before the US-led war against Iran. The President's plan would also reduce spending on non-defence programmes by 10 per cent by shifting some responsibilities to state and local governments.

“President Trump is committed to rebuilding our military to secure peace through strength,” the budget said.

The President's annual budget is considered a reflection of the administration's values and does not carry the force of law. The massive document typically highlights an administration's priorities, but Congress, which handles federal spending issues, is free to reject it and often does.

This year's White House document, prepared by Budget Director Russ Vought, is intended to provide a road map from the President to Congress as lawmakers build their own budgets and annual appropriations bills to keep the government funded. Vought spoke to House GOP lawmakers on a private call Thursday.

Trump, speaking ahead of an address to the nation this week about the Iran war, signalled the military is his priority, setting up a clash ahead in Congress.

“We're fighting wars. We can't take care of day care,” Trump said at a private White House event Wednesday.

“It's not possible for us to take care of day care, Medicaid, Medicare – all these individual things,” he said. “They can do it on a state basis. You can't do it on a federal.”