NEW YORK (AP) – Apple Inc. on Friday said it is suing cell phone-maker Nokia Corp. for patent infringement, a countermove to Nokia's suit against technologies used in Apple's iPhone.

Apple's lawsuit claims Nokia is infringing on 13 of Apple's patents and says the Finland-based company chose to "copy the iPhone," especially its user interface, to make up for its declining share of the high-end phone market.

A Nokia representative could not immediately be reached for comment Friday morning.

In October, Nokia filed a lawsuit in U.S. federal court claiming Apple, based in Cupertino, Calif., infringes on 10 of its patents.

Countersuits are a staple of patent litigation, which often ends in cross-licensing agreements.

Both suits were filed in federal court in Delaware.

U.S.-traded shares of Nokia rose 27 cents, or 2.2 percent, to $12.83 in morning trading, while Apple's shares slid 62 cents to $195.81.

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