InterDigital that owns about 1,300 U.S. patents related to mobile phones, said Tuesday it filed a patent-infringement complaint against Nokia Oyj, ZTE Corp., and Huawei Technologies Co.

InterDigital filed a case with the U.S. International Trade Commission in Washington, alleging infringement of seven patents related to so-called third-generation wireless technology, InterDigital said in a statement. The company also sued the phone-makers in federal court in Wilmington, making the same allegations.

The company last week hired Evercore Partners Inc. and Barclays Capital to help explore a potential sale of its assets to take advantage of increased demand for wireless patents.

InterDigital, whose stock has risen more than 70 percent in the last week, has said its patents are deeper and stronger than those that Nortel Networks Corp. auctioned for $4.5 billion in bidding that concluded June 30.

"Over the past thirty years, InterDigital has invested nearly one billion dollars in the development of advanced digital cellular technologies, creating important innovations, and helping to drive an industry creating billions of wireless connections," Lawrence Shay, head of InterDigital's patent holding units, said in the statement.

InterDigital said it filed the ITC complaint because Nokia, ZTE, and Huawei refused to pay licensing fees. InterDigital already had a case against Nokia at the ITC that it lost and is awaiting an appeals court ruling in that dispute.