U.S. stock index futures stutter-stepped Tuesday, amid investor caution ahead of the start of the two-day Federal Reserve meeting.

European and Asian shares were also lower, reversing Monday's risk rally.

U.S. stocks edged higher on Tuesday, ahead to the Federal Reserve’s two-day policy meeting where the FOMC will debate whether to scale back the central bank’s stimulus program from $85 billion per month to $70 billion to $75 billion.

On the economic front, consumer prices ticked up 0.1 percent in August as the cost of energy fell, according to the Labor Department. Economists polled by Reuters had expected a gain of 0.2 percent.

Also on Tuesday, the National Association of Home Builders (NAHB) said its housing-market index remained flat at 58 this month, as August’s figure was revised slightly downward from 59 to 58.

The Dow Jones industrial average rose 39.68 points or 0.26 percent, to 15,534.46. The S&P 500 gained 5.68 points or 0.33 percent, to 1,703.27. The Nasdaq Composite added 18.41 points or 0.5 percent, to 3,736.38.

Video Credit: Reuters