Tariff-driven uncertainty has led consumers, businesses and even the Fed to adopt a wait-and-watch mode. The Fed starts its two-day meeting on Tuesday, with the central bank widely expected to stay put on interest rates. Comments from policymakers will be scrutinized for any clues hinting at where they stand on monetary policy easing this year.

Investors were feeling on edge Tuesday as uncertainty about President Donald Trump's trade policies looked set to drag down the blue-chip U.S. stock indexes. The Cboe Volatility Index, a widely followed fear gauge that tracks S&P 500 options contracts and trades under the ticker VIX,

Wall Street's main indexes fell on Monday after U.S. President Donald Trump rekindled worries about the fallout of a global trade war by introducing new tariffs, while focus remained on the Federal Reserve's monetary policy decision later this week.