Sales figures from European launches have yet to be added into the total.

More than 1.4 million people have gone online to play the title since its launch and more than four million online games of Halo 3 were logged in the last 24 hours.

"Halo 3 has become a pop-culture phenomenon," said Shane Kim, corporate vice president of Microsoft Game Studios, in a statement.

Microsoft needs Halo 3 to boost sales of the Xbox 360; despite investing billions of dollars into the Xbox project it has yet to see any meaningful profitable return.

"It's far too early to say what the financial return will be for our investment," Mr Kim told the BBC News website last month.

Microsoft hopes to make a profit on its Xbox in this financial year.

"If we can't make a profit in the year Halo 3 comes out, then when will we?" said Mr Kim.

Microsoft has started a disc replacement service for gamers complaining of scratched copies of a limited edition version of the game.

But gamers have complained it will take two weeks for replacement copies to arrive.