Citing reports from unnamed retailers, Microsoft today said the Xbox 360 outsold Sony's PlayStation 3 by a three-to-one ratio in the U.S. on Black Friday and over the first weekend of the holiday shopping season. The numbers suggest that the Xbox 360's pre-holiday price cuts are boosting unit sales of the Microsoft console.

But these types of estimates have been a big bone of contention between Sony and Microsoft in the past. At the beginning of the 2007 holiday season, for example, Microsoft claimed a two-to-one sales lead over the PlayStation 3, but Sony called those numbers "way off" at the time.

I've put a message in to a Sony Computer Entertainment America representative to get the company's take on the latest Microsoft numbers, and I'll update this post depending on the response.

Microsoft didn't disclose worldwide Xbox 360 sales for the Black Friday weekend, but it said sales of the console are up as much as 400 percent in Europe since the September price drop.

The Xbox 360 ranges in price from $199.99 to $399.99, depending on storage capacity and other options. The PlayStation 3 sells for $399.99 and $499.99. Nintendo's market-leading Wii console goes for $249.

The Xbox 360 and PS3 were neck-and-neck in year-to-date U.S. unit sales coming in to the holiday season, according to NPD Group data. In cumulative U.S. sales, the Xbox 360 continues to benefit from its year-long head start, maintaining a sizable lead over the PS3, but coming in second to the Wii in that measure, as well.