CHICAGO (REUTERS, AFP) - President Donald Trump will propose drastic cuts to America's foreign aid and environmental programs in a security-heavy first budget blueprint to be released later Thursday.

In a plan designed to translate bold campaign promises into dollar and cent commitments, the Republican leader will propose a 28 per cent cut in State Department funding. That could be a harbinger of steep reductions in foreign aid and funding to UN agencies, with knock-on effects around the world.

The Pentagon will be the major winner with a nearly 10 per cent boost - shoveling more cash toward a defense budget already greater than that of the next seven nations combined. The cost to healthcare companies for US regulatory review of their products, including drugs and medical devices, would more than double under the Trump administration's proposed 2018 budget.

The budget proposal for the fiscal year beginning on Oct. 1 is a first shot in a battle with Congress - which controls the government's purse strings - that will play out over months and may yield spending levels far from those Trump requested.

Congress, controlled by Mr Trump's fellow Republicans, may reject some or many of the cuts to the US State Department and Agency for International Development (USAID) budgets, which pay for everything from maintaining America's diplomatic corps to fighting poverty, promoting human rights and improving health in foreign nations.

The White House is proposing a combined US$25.6 billion budget for the State Department and USAID, a 28 per cent reduction from current spending, according to documents provided by the White House on Thursday.

"It is time to prioritize the security and wellbeing of Americans, and to ask the rest of the world to step up and pay its fair share," Mr Trump said in a letter introducing his budget, which calls for large increases in U.S. defense spending. "This is a 'hard power' budget. It is not a 'soft power'budget," Mick Mulvaney, Mr Trump's budget director, told reporters, referring to the president's desire to prioritize military power over the influence that can flow from development aid.

The budget also requests US$12 billion in "Overseas Contingency Operations," or OCO, funding for extraordinary costs, chiefly in war zones such as Afghanistan, Iraq and Syria. No comparison was provided for the current year's OCO spending.

It has proposed eliminating an international food aid program, halting funding for clean water initiative in rural areas and reducing county-level staff for a 21 per cent drop in discretionary spending at the Agriculture Department, according to a White House budget document.

The proposal would save US$498 million (S$704.5 million) by eliminating a rural water and wastewater loan and grant program, which the White House proposal said was duplicative. The program helps fund clean water and sewer systems in communities with less than 10,000 people.