New York:, the world's largest online retailer, said customers have bought about 1 million of its Kindle e-book readers and tablets in each of the past three weeks, the most detailed sales numbers the company has released.

The Kindle Fire tablet, which sells for $199 (Dh730), has been the best-selling product on since its introduction 11 weeks ago, the Seattle-based company said in a statement. Kindle Fire sales have risen week-over-week for three weeks now, Amazon said.

The Kindle Fire, which has a 7-inch (18-centimetre) display and runs on Google's Android operating system, costs less than half the price of Apple's least-expensive iPad tablet. Amazon chief executive officer Jeff Bezos said in October that the company may post a loss in the fourth quarter as it ramps up spending. Operating margin may narrow to 0.79 per cent this quarter from 3.66 per cent in the year-earlier period, according to the average analyst estimate compiled by Bloomberg.

"They have not talked about numbers at all, so it's a big deal that they for some reason think they need to disclose metrics now," said Brian Blair, an analyst at Wedge Partners in New York.

Amazon shares jumped 0.6 per cent to $181.26 Thursday at the close in New York. The stock is little changed this year.