Apple Inc. pulled its iPad 2 tablet from the websites of some unauthorized merchants in China, including Amazon.com Inc.'s Chinese site, in the latest challenge for the consumer-electronics giant in a key growth market.

Apple requested that the iPad 2 be removed from online storefronts because the sites weren't authorized to sell the device, according to people with knowledge of the matter. The people said that the removal wasn't related to a long-running dispute over the iPad trademark in China.

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