The White House declined comment on the Bloomberg report, which cited six unidentified sources, and deflated markets. The S&P hit session lows, and the US dollar, Chinese yuan and US Treasury yields also fell.

Trump has credited his electoral success to his hard line on trade, which he has argued hurts US workers and favors foreign competitors. Washington is demanding Beijing improve market access and intellectual property protections for US companies, cut industrial subsidies and slash a $375 billion trade gap.

The world's two largest economies have already applied tariffs to $50 billion of each other's goods in a tit-for-tat trade war. Talks aimed at easing tensions ended last week without major breakthroughs.

The new proposed 25 percent tariffs would affect consumer products including home building supplies, technology products, bicycles and apparel.

A public comment period on the proposal is set to end on Sept. 6, and Trump plans to impose the tariffs after that deadline, Bloomberg said.

Some sources said Trump had not made his final decision, the Bloomberg report said. Trump administration officials have been divided over how hard to push Beijing.

Trump, who has threatened to impose duties on virtually all of the more than $500 billion of Chinese goods exported to the United States each year, told Reuters in an interview earlier this month that resolving the trade war with China would "take time" and that he had "no time frame" for ending it.

The report on Trump's China stance coincides with US negotiators pushing to hammer out a deal with Canadian counterparts to overhaul the North American Free Trade Agreement.