The countdown is on for the Fed's rate decision on Wednesday as policymakers begin their two-day meeting. Although the central bank is expected to keep rates unchanged, Wall Street will listen closely to Chair Jerome Powell's comments on how the economy is holding up.

Stock futures are lower Tuesday as investors react to a steady stream of earnings reports while awaiting news on tariffs and the results of the two-day Federal Reserve meeting that is set to start today.

The S&P 500 and the Nasdaq were lower 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.