U.S. stock index futures point to a mixed open on Tuesday after the major U.S. indices retreated from their rally on Monday as uncertainties over the future of the Fed's stimulus program loom large.

Futures on the Dow Jones Industrial Average were up 0.05 percent, while futures on the Standard & Poor's 500 Index were down 0.06 percent. Futures on the Nasdaq Composite Index were down 0.06 percent.

The markets eagerly await Federal Reserve Chairman Ben Bernanke's testimony on the country's economic outlook and recent monetary policy actions before the Joint Economic Committee, in Washington, D.C., on Wednesday. 

Many investors will closely watch the Federal Reserve Chairman’s comments for hints on the future of the Fed's bond-buying program. His testimony is likely to provide hints on the time line of the proposed rollback of the Fed's bond-buying program. 

Speculations that Federal Reserve is likely to end the massive stimulus measures that have been fueling the economy since late 2008 had ushered in volatility across global stock markets in recent weeks.

Also, investors are likely to focus on the International Council of Shopping Centers’ ICSC-Goldman Store Sales index, due to be released at 8:30 a.m. EDT, on Tuesday. The weekly index, a measure of comparable store sales at major retail chains, is related to the general merchandise portion of retail sales and is an indicator of consumer spending. 

The Johnson Redbook Index, a proprietary indicator of growth in retail sales that provides advanced estimates of trends in retail sales, is due to be released at 8:55 a.m. EDT.

On Monday, the major U.S. indices finished in the red after both the Dow and the S&P 500 Index posted record highs during intraday trade as uncertainty over the Federal Reserve’s continuation of the stimulus program weighed on investor sentiment.     

The Dow Jones Industrial Average slipped 19.12 points, or 0.12 percent, to 15,335.28 at the close. The Standard & Poor's 500 Index shed 1.18 points, or 0.07 percent, to finish at 1,666.29. The Nasdaq Composite Index declined 2.53 points, or 0.07 percent, to end at 3,496.43.

Most European markets traded in the red on Tuesday as many investors eagerly await the Fed statement on the future of its bond-buying program.

The London's FTSE 100 was down 0.11 percent, Germany's DAX-30 index lost 0.38 percent and France's CAC-40 fell 0.36 percent.

Earlier in the day, Asian markets traded on a mixed note after the Street on Monday retreated from its record-setting rally as investors treaded cautiously on the back of uncertainty over the Fed's stimulus program.

Hong Kong’s Hang Seng Index fell 0.54 percent to end at 23,366.37, Japan’s Nikkei closed up 0.13 percent at 15,381.02, and China's Shanghai Composite Index rose 0.22 percent to 2,305.11. South Korea's KOSPI dropped 0.07 percent to 1,981.09.