Futures on major U.S. stock indices point to a slightly lower opening Tuesday ahead of existing home sales data that are expected to show a rise in April sales.

Futures on the S&P 500 are down 0.07 percent, futures on the Dow Jones Industrial Average are down 0.14 percent and Nasdaq 100 futures are down 0.04 percent.

Investors are likely to focus on existing home sales data as lackluster economic data earlier this month including nonfarm payrolls, ISM services and retail sales fueled concern that the strength of recovery in the world's largest economy is faltering.

Better-than-expected reports on housing starts and industrial production in the last week though suggested the housing market recovery was gaining some traction amid a moderate pickup in economic growth early in the second quarter.

The National Association of Realtors (NAR) is due to report the sales of previously occupied homes after the market opens. Economists are forecasting that existing home sales in April may rise to 4.64 million from 4.48 million in March.

Existing home sales, which measure the annualized number of existing residential buildings that were sold during the previous month, declined for the second month in March and missed expectations. Sales fell by 2.6 percent in March to an annual rate of 4.48 million from an upwardly revised annual rate of 4.6 million in February and also fell short of Reuters estimation of 4.26 million.

On the earnings front, a string of companies including AutoZone, Dell, Guess, Analog Devices, Ralph Lauren, Avago Technologies, DSW, PetSmart and Collective Brands will report their quarterly results.

In Europe, stock markets were higher. Germany's DAX 30 rose 42.77 points, France's CAC 40 rose 15.15 points and London's FTSE 100 index rose 42.30 points.

Asian stock markets ended higher for the second day Tuesday, as China promised to spur growth and France and Germany agreed to prevent Greece from exiting the euro zone.