Data also showed a drop in US consumer confidence in September, adding to the negative factors affecting stocks, analysts said.
After starting the day higher, major indices fell into the red at mid-morning and stayed in negative territory the rest of the day.
The Dow Jones Industrial Average finished at 26,807.77, down 0.5 percent.
The broad-based S&P 500 shed 0.8 percent, settling at 2,966.60, while the tech-rich Nasdaq Composite Index slumped 1.5 percent to 7,993.63.
Worries about trade have been on the market’s mind for more than a year, leading to occasional selloffs, but Trump’s UN address adopted a tough line ahead of talks in October.
Trump bashed China over its “abuses” of the international trade system and declared that “I will not accept a bad deal for the American people.”
But the US president also found himself on the defensive as Democratic leaders signalled they expect to launch an impeachment investigation.
Democrats accuse Trump of an abuse of power in a reported attempt to pressure the newly installed president of Ukraine to open a corruption investigation into his lead challenger for the White House, Joe Biden, and Biden’s son Hunter.
Art Hogan, chief market strategist at National Securities, said the push towards impeachment added to investor unease.
“The market doesn’t have a good template for what that means,” Hogan said.
“Anything that might make a dent in consumer confidence would be a negative.” (AFP)