US stocks retreated from a historic run of gains on Monday as President Trump's new tariff threat revived trade war worries in the wait for a Federal Reserve policy decision. The US dollar (DX=F) also lost ground as Wall Street gauges whether recent confidence that Trump has moved to a dealmaking phase is misplaced.

Investors kickoff the week awaiting more developments on President Trump’s trade deals and the decision on interest rates by the Federal Reserve out Wednesday. Optimism is improving after the S&P 500 notched the longest winning streak in 20 years last week.

U.S. stock index futures fell on Monday after President Donald Trump reignited concerns about the effects of a global trade war by introducing new tariffs, while markets awaited the Federal Reserve's monetary policy decision this week.