U.S. stock index futures pointed to a weaker open on Tuesday, putting the S&P on track for a fifth day of losses as persistent concerns over Europe and a weaker reading on economic growth kept investors on edge.

The U.S. economy grew at a slower pace than previously estimated in the third quarter, a troubling sign as investors worry about the pace of expansion. Gross domestic product grew at a 2 percent annual rate in the quarter, down from a previous estimate of 2.5 percent.

The data came on top of other headwinds that have discouraged buyers of riskier assets. The worries about debt both in the United States and Europe spurred losses of almost 2 percent for the S&P 500 on Monday, while the Dow turned negative for the year. Last week, the S&P recorded its worst week in two months.

The GDP data is a continuation of the general economic malaise we've seen internationally, said Michael Mullaney, a portfolio manager who helps manage $9.5 billion at Fiduciary Trust Co in Boston.

It's going to be tough sailing with no real clear-cut signs of global growth, coupled with the geopolitical situation on a worldwide basis.

The FTSEurofirst 300 <.FTEU3> fell 0.2 percent after rising earlier in the day. The session was volatile after yields in a Spanish government debt auction rose to their highest in 14 years.

S&P 500 futures fell 4.1 points and were below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 47 points and Nasdaq 100 futures sank 13.5 points.

The S&P has fallen through a key support level at 1,200. The next technical support was seen at 1,187, representing the 61.8 percent retracement of the 2011 high to low.

We're in a range between about 1,180 and 1,250 on the S&P, and we're unlikely to break out of that until we see real policy changes get implemented in Europe, said Art Hogan, managing director of Lazard Capital Markets in New York. However, we do have a higher floor for markets than a month ago, and that's positive.

Technology shares will be in focus a day after Hewlett-Packard Co projected fiscal 2012 earnings would be at least $4 per share versus Wall Street estimates of $4.54. The Dow component also reported a steep drop in quarterly profit. The stock fell 1.7 percent to $26.39 in premarket trading.

Late Monday, the co-chairs of a special U.S. congressional committee said it failed to reach a deal on reducing government deficits. There are concerns the stalemate will make it more difficult to pass extensions of stimulative measures like payroll tax cuts, which could hurt the U.S. economy.

While the news was expected, it could further limit market upside. Trading volume is likely to be low this week as global uncertainties and a trading week shortened by the U.S. Thanksgiving holiday prompt investors to sit on the sidelines.

Campbell Soup Co reported first-quarter earnings that beat expectations while sales were slightly below consensus. Medtronic Inc also reported profit above estimates, and the stock rose 3.5 percent to $34.45 before the bell.

(Editing by Jeffrey Benkoe)