Qualcomm has sued Apple accusing the iPhone maker of failing to abide by the terms of a software license and said it may have used its access to that code to help Intel.

The chipmaker filed the lawsuit against Apple on Wednesday in California state court in San Diego, adding yet another front to their bitter legal battle. Apple is being sued for breach of a contract that governs the use of software needed to make chips work with other parts of mobile phones and communicate with networks.

The two companies are embroiled in a dispute over technology licensing fees that Qualcomm charges for patents that cover the basics of how mobile phone systems work. Apple says Qualcomm is unfairly charging too much and leveraging its strong market position in chips illegally. Qualcomm has countered that Apple, one of its largest customers, has lied to regulators in an unfair attempt to bully it into charging less.