Microsoft Corp., striving to make its Xbox video-game unit profitable, said "Halo 3" brought in $300 million in revenue over its first week, becoming the fastest-selling video game.

More than 2.7 million people played the alien-shooting title online in the first week, Redmond, Wash.-based Microsoft said. The world's biggest software maker released "Halo 3" worldwide on Sept. 25.

Sales of the Xbox 360 more than doubled compared with the weekly average before the debut of "Halo 3," Microsoft said. That may help the company narrow the gap with Nintendo Co.'s Wii system, which has outsold the Xbox 360 in the U.S. since at least January, according to researcher NPD Group Inc.

"We definitely anticipated a pretty strong release," CIBC World Markets' Brad Reback said in an interview. The Atlanta-based analyst said $300 million was at the high end of the range he estimated.

Nintendo's Wii sold about 400,000 units in August to Microsoft's 277,000, according to Port Washington, N.Y.-based NPD. Since its debut in November 2006, the Wii has sold 4 million units in the U.S. The Xbox, which came out a full year earlier than the Nintendo system, has sold 6.3 million.

The company said last week that the new game rang up $170 million in sales on its first day in U.S. stores, making "Halo 3" a bigger entertainment release than the final Harry Potter novel or the film "Spider-Man 3."

Users play as a genetically engineered soldier defending humankind against an alien race. Today the company called the title "one of the most successful entertainment properties in history."

Microsoft pledged to turn a profit in the Xbox division in this fiscal year, following $7 billion in losses since the first Xbox was sold in 2001. Microsoft cut the price of the console by $50 to $349.99 in August to coincide with the release of Electronic Arts Inc.'s "Madden NFL 08" game and compete more with the Wii, which sells for $249.

In July, Nintendo reported that first-quarter profit rose to a record on Wii sales, to $668 million. The company raised its full- year profit forecast in anticipation of increasing sales of accessories for the console.

Sony Corp.'s PlayStation 3 is the most expensive of the three gaming systems, with a price of $499.99 for a version that has 60 gigabytes of space.

Sony cut the price on the PlayStation in July.

Both the PlayStation and the Xbox count younger males among their main users, CIBC's Reback said. "Halo 3" may help Microsoft win holiday shoppers away from Sony's product because the game is exclusive to the Xbox system, he said.