Activision Blizzard Inc said its video game Call of Duty: Modern Warfare 2 scored record sales of $550 million in its first five days, but the company is still concerned about weak consumer spending.

The game, a first-person-shooter that lets gamers portray elite soldiers hunting down targets in locations ranging from South America to Afghanistan, beat last year's blockbuster Grand Theft Auto IV from Take-Two Interactive Software Inc which sold more than $500 million in its first week.

Activision did not say how many units were sold in the period. Last week it said it sold 4.7 million copies for sales of $310 million on its first day in the U.S. and United Kingdom alone.

Analysts' sales estimates for the $60 game range from 11 million to 13 million units by the end of 2009. There is plenty at stake for Activision since Call of Duty is likely to account for a sizable chunk of the company's profits in the fourth quarter, analysts say.

Shares of the company, which have risen around 35 percent and outperformed chief rival Electronic Arts Inc's 11 percent gain, rose 5 cents in early trade on Wednesday to $11.74.

Still, chief executive Bobby Kotick was mindful of the weak economy, which has stung the video game industry this year as consumers think twice about buying game machines and software.

Despite the success of 'Call of Duty: Modern Warfare 2', Activision Blizzard remains cautious about the U.S. and global economy as well as other variables that can affect industry fundamentals and our own performance, including consumer spending which remains a significant concern, he said in a statement.

Price cuts from home console makers Nintendo Co, Microsoft Corp and Sony Corp had been expected to help boost software sales since September, but have so far proven to have little affect on game sales.

Sales of video game equipment and software in the United States tumbled 19 percent in October to $1.07 billion, according to research group NPD. [ID:nN12407998]

(Reporting by Franklin Paul; Editing by Derek Caney)