Microsoft has quietly cut the price of its entry-level Surface tablet computer by some 30 percent, after surveys indicating sluggish sales.

The Surface RT tablet was being sold for as low as $349 for US customers on the Microsoft website on Monday, down from the introductory price last year of $499.

The move comes amid a price war for tablets and a flood of new devices on the market.

Amazon has slashed prices of its Kindle HD tablets to as low as $169 in the US and 139 pounds in Britain, while Barnes & Noble has cut the price of its Nook to as low as $129, and has announced plans to outsource production of its tablets.

Microsoft introduced its Surface last year at a premium price, promoting the device as a substitute for a personal computer with an attachable keyboard.

But a survey by the research firm IDC estimated the company sold just 900,000 units in the first quarter, in a global market of some 49 million.

Microsoft previously cut the price of the Surface as low as $199 for education buyers.