Midway veep Martin Spiess has said the Xbox 360's performance in some European countries is a concern, and that it's "lagging behind" its competitors.
"I don't know what it's like for other companies, but the market is not as big as the US market, so naturally we have lower attachment rates," Spiess told GamesIndustry.biz.
"But it could be growing to the same size as the US - the only problem we have right now is that we see in certain territories Microsoft is lagging behind. Sony has become very strong, Nintendo has become very strong, but the Microsoft market in certain territories is concerning."
Microsoft is well aware of its weakness in certain markets, of course, and recently installed Chris Lewis as head of its Interactive Entertainment Business for Europe, among other measures, to try and address the problem.
Speaking to Eurogamer at GDC earlier this year, Xbox Live boss John Schappert - number two to Don Mattrick, head of the Xbox business - said Southern Europe was a particular concern.
"We look, and we are hitting the ball out of the park in North America, and I think that there's regions of Europe where we're not doing as well as we'd like to do, and we have room for improvement," he said. "Those are renewed areas and key areas of focus for us."