Microsoft has sold more than 10 million Xbox 360 consoles in the US.
The milestone means that the Xbox 360 is the first next-generation console (along with the Wii and PlayStation 3) to surpass the 10 million mark in the US.
Microsoft estimates that more than 19 million Xbox 360s have been sold worldwide.
"This year will be the largest in the history of the video game industry, with Xbox 360 leading the charge in the US and abroad," said Don Mattrick, senior vice president of Microsoft's interactive entertainment business.
"History has shown that the first company to reach 10 million in console sales wins the generation battle. We are uniquely positioned to set a new benchmark for the industry."
Recent figures from research firm NPD Group suggest that Nintendo is hot on Microsoft's heels in the US, logging 8.8 million Wii sales. The PS3, meanwhile, has racked up 4.1 million US sales since its launch at the end of 2006.
Microsoft used the occasion to mark another milestone for its Xbox Live service, announcing that the online gaming network has signed up more than 12 million subscribers globally.
Microsoft has struck a deal with Grand Theft Auto publisher Rockstar Games to distribute add-ons to the game exclusively through Xbox Live.
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