U.S. stocks opened higher Tuesday as the Federal Reserve kicked off its two-day policy meeting.

Analysts widely expected the U.S. central bank to raise interest rates by a quarter point at this meeting. Market expectations for a June rate hike were 99.6 percent Tuesday, according to the CME Group's FedWatch tool.

Investors will also watch closely any clues about how the Federal Reserve plans to unwind its massive 4.5 trillion U.S. dollars balance sheet.

On the economic front, the Producer Price Index for final demand was unchanged in May yet seasonally adjusted, the U.S. Labor Department reported Tuesday.

On an unadjusted basis, the final demand index increased 2.4 percent for the 12 months that ended in May.

Shortly after the opening bell, the Dow Jones Industrial Average rose 38.79 points, or 0.18 percent, to 21,274.46. The S&P 500 added 7.04 points, or 0.29 percent, to 2,436.43. The Nasdaq Composite Index was up 37.73 points, or 0.61 percent, to 6,213.20.

On Monday, the U.S. stocks declined, as the underperformance of tech shares, including those of Apple, Amazon, Alphabet and Facebook, continued to weigh on the market.