Stock index futures fell before the open Tuesday as the market struggled to move past recent highs.
On Monday, the market eked out modest gains, although the Dow hit its highest level since June 2008. The Nasdaq, however, fell slightly.
One concern for investors are persistently high oil prices. London Brent crude rose to near 2 1/2-year highs, with continuing violence in the Middle East and North Africa supporting prices, while U.S. light crude traded above $108 a barrel.
In Europe, Moody's Investor's Service downgraded Portugal'ssovereign debt by one notch, reigniting fears that the country will need to seek a bailout.
Concerns over global growth were also fueled by a survey published in the Nikkei business newspaper which showed economists expect the Japanese economy to contract by 0.6 percent for the January-March quarter and by 2.6 percent in the three months to the end of June.
They expect growth quarter in the world’s third-largest economy to return in the July to September, the survey found.
Also, investors were digesting comments made by Federal Reserve President Ben Bernanke Monday evening which suggested the Fed is not yet ready to start tightening monetary policy despite an improving economy.