U.S. stock index futures were down on Tuesday, pulling back after a sharp rally fueled by a U.S.-China trade truce, as investors turned their focus to a key U.S. inflation reading that could shape the outlook for monetary policy.

Wall Street was on track to open with losses as the initial euphoria over the 90-day truce in the U.S.-China trade war faded.

Excitement over the surprise trade-war truce between the US and China has quickly turned to caution, as the reality of a more subdued business environment than in the past returned to view. Stocks in Hong Kong slumped as much as 1.