An influential U.S. consumer watchdog is investigating online reports that Apple Inc's new iPad throws off an unusually large amount of heat and will publish its findings later on Tuesday.

Consumer Reports, which reviews everything from electronics to cars, noticed comments on online forums and on Apple's website about excessive heat from the new device, which went on sale Friday, and decided to look into the issue, a spokesman said.

The group will publish its findings on Tuesday after finishing a battery of tests, the spokesman added.

An Apple spokeswoman said the iPad was within our thermal specifications.

The company's shares were down 0.8 percent at about $596 at midday.

The third iteration of the iPad hit store shelves on Friday and about 3 million units have moved so far, the company has said.

Reviews have generally been good for a gadget that experts say falls short of being revolutionary, focusing on the iPad's ability to take advantage of faster 4G wireless technology as well as a sharper display.

On Friday, before comments about excessive heat began circulating online, Consumer Reports said in its preliminary review that the iPad was shaping up as the best tablet yet.

(Reporting by Edwin Chan and Poornima Gupta; editing by Lisa Von Ahn and Andre Grenon)

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