U.S. stocks opened mixed Tuesday as investors assessed the timing of the next interest rate hike by the Federal Reserve.

Fed Vice Chairman Stanley Fischer said early Tuesday that it is impossible to say whether the next interest rate hike would be "one and done," according to media reports.

Fischer's comments were in line with remarks he and Fed Chairperson Janet Yellen made on Friday at a conference in Jackson Hole, Wyoming, indicating that the time to lift rates again was nearing.

"In light of the continued solid performance of the labor market and our outlook for economic activity and inflation, I believe the case for an increase in the federal funds rate has strengthened in recent months," Yellen said Friday.

Analysts said it is possible for the Fed to hike interest rates as soon as September. But about 71 percent of 62 economists surveyed by the Wall Street Journal this month believed that the Fed will wait until December to raise rates.

On the economic front, U.S. consumer confidence is scheduled to be released later on Tuesday.

Shortly after the opening bell, the Dow Jones Industrial Average rose 6.44 points, or 0.03 percent, at 18,509.43. The S&P 500 edged up 0.94 point, or 0.04 percent, to 2,181.32. The Nasdaq Composite Index edged down 1.07 points, or 0.02 percent, to 5,231.25.

Source : XINHUA