Activision has announced that combined data from NPD, Chart Track and GfK shows that Call of Duty 4: Modern Warfare was the best-selling game worldwide in 2007.

Since release in November, the game has sold over seven million units and has also become the most popular game played on Microsoft' s Xbox Live service.

" We' re very excited about this achievement especially given so many competitive titles this year," said Will Kassoy, senior vice president of Activision.

" Consumer and critics agree that Call of Duty 4: Modern Warfare is one of the best games ever created and further establishes Call of Duty as one of the premier brands in the industry. This ground-breaking game and franchise continue to establish new standards by which all other action games will be judged," he added.