Qualcomm is suing four Apple suppliers over withholding royalties, Reuters reports. The move is the latest in an ongoing battle between Qualcomm and Apple over licensing payments Qualcomm charges for the use of patents the company holds on several integral components used in iPhones. Apple suspended all licensing payments to Qualcomm last month, and Qualcomm’s latest filing goes after Foxconn, Pegatron, Wistron and Compal Electronics for their part in the proxy war. “While not disputing their contractual obligations to pay for the use of Qualcomm’s inventions, the manufacturers say they must follow Apple’s instructions not to pay,” Qualcomm said in a statement. Apple has agreed to indemnify its partners against any damages resulting from their refusal to pay Qualcomm, but Qualcomm is now seeking a court order to force the manufacturers to comply with existing contractual obligations.