US citizens looking to buy a Microsoft Xbox 360 may be out of luck this Christmas, with many shops and online services reporting that they have no more in supply and do not expect to be able to stock up due to a lack of new shipments.

One consumer who heard that Best Buy stores had stocked up said: "I was going to camp out (early Sunday), but when I got there I found people who had already gotten there at 7 p.m. Friday," and instead ordered the system on the company's Web site.

Microsoft has been plagued by a supply shortage in regards to the console system, but remains optimistic that it will meet its sales goals of 3 million units globally in the first 90 days of release.