HELSINKI (Reuters) - The world's top cellphone maker Nokia said on Tuesday the U.S. International Trade Commission has decided to start investigating Qualcomm Inc's trade practices and alleged patent infringement.

Nokia filed the complaint last month requesting ITC to ban U.S. imports of certain Qualcomm chipsets that infringe Nokia patents.

"We believe there is significant evidence that Qualcomm has copied Nokia's patented technology without permission and has used these innovations in certain GSM/WCDMA and CDMA2000 chipsets," a Nokia spokeswoman said.

Qualcomm was not immediately available for comment.

Nokia and Qualcomm have been in a legal dispute after part of a licensing deal over technology patents expired on April 9.

Their increasingly bitter fight is worrying investors and the industry on both sides of the Atlantic.

Nokia filed the complaint to ITC last month as a response to Qualcomm's ITC case filed in June 2006. ITC opened a hearing in that case last week.
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