SAN FRANCISCO - MICROSOFT said that its Halo 3 video game racked up worldwide sales of US$300 million (S$444 million) in its first week, making it one of the year's best sellers and helping to more than double sales of its Xbox 360 console.

The news on Thursday builds on Microsoft's previous announcement that the final chapter in its series of alien-battling shooting games did US$170 million in sales in the first 24 hours after its Sept 25 debut.

The game is crucial to Microsoft's efforts to establish dominance in the US$30 billion global video game industry that has been dominated by Sony the past few years.

Microsoft also competes against Nintendo's Wii console, which has enjoyed stronger sales this year.

'Initial reports from retailers worldwide show console sales have more than doubled compared with the weekly average before the launch of Halo 3,' Microsoft said in a statement.

Microsoft did not elaborate, but industry figures show that the company sold 277,000 Xbox 360 units in the United States in August and just over 11,000 units in Japan in that month.

Microsoft also said Halo 3, which lets people play the game together or battle each other over the Internet, had spurred a 'record number' of people to sign up for its paid Xbox Live online service.

The company said all three Halo games had sold more than 20 million copies. Earlier this year, Microsoft said the first two games had sold 14.8 million copies, which could mean Halo 3 has sold as many as 5.2 million copies. -- REUTERS