NEW YORK (CNN/Money ) – "Halo 2" has claimed early bragging rights in the 2004 video game battle.

In its first 24 hours of retail availability, the flagship title for Microsoft's Xbox gaming system sold approximately 340,000 copies more than "Grand Theft Auto: San Andreas" did in its first six days on shelves.

Microsoft announced late Wednesday that retailers sold 2.4 million copies of "Halo 2" on Tuesday, racking up sales of $125 million -- 25 percent higher than what Peter Moore, vice president of Microsoft's games division, predicted at a Harris Nesbitt investment conference Tuesday.

Take-Two Interactive Software (Research), which publishes the "Grand Theft Auto" games, does not disclose internal sales numbers, but the NPD Group -- a third-party organization that tracks video game sales -- reported "San Andreas" sold 2.06 million copies in October. The game began selling Oct. 26.

Analysts had expected "San Andreas" to sell somewhere in the neighborhood of 2.5 million copies in October.

Each game is exclusive to a specific console at this point. "Halo 2" can be played only by Xbox owners, while "Grand Theft Auto: San Andreas" can only be played on the PlayStation 2.

Both games are widely expected to be the top sellers in the gaming industry in 2004. Most analysts believe "Grand Theft Auto" will ultimately sell more copies, due to the significantly larger number of PS2 owners. There are 9.8 million Xboxes in homes around the country, compared to 24.9 million PlayStation 2s.

Still, Microsoft's (Research) massive marketing campaign, estimated to be in the tens of millions of dollars, created an aura of excitement that prompted gamers to respond. Fans lined up outside some 7,000 retail stores for up to 15 hours before "Halo 2" went on sale at midnight Tuesday morning. Moore on Tuesday said one retailer had sold 200,000 copies of the game before daybreak. Game specialty retailer GameStop (Research) reported first day sales of over a half-million copies.

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The popularity of "Halo 2" is also having a ripple effect on other segments of the video game industry.

Prima, a division of Random House, sold over 270,000 copies of its Halo 2 strategy guide Tuesday. That's the best first-day sale of a Random House book since the release of former president Bill Clinton's autobiography.