Qualcomm plans to ask the U.S. International Trade Commission to block imports of iPhones, according to a report. The move apparently was spurred by Apple’s recent decision to stop making royalty payments owed under a licensing agreement between the two companies, which is the subject of a billion-dollar legal battle in federal court. Qualcomm last month announced that for the quarter ended March 31 Apple had withheld payments to its contract manufacturers for royalties owed under a licensing deal for technology used in the iPhone.