The company also called Qualcomm's lawsuit "a blatant effort to take credit for the innovation of others".
Qualcomm's claims came the same day Apple said in a separate suit - which Qualcomm brought in July over six different patents - that the electronics company's Snapdragon phone chips infringed eight of Apple's own patents. More recently, Apple reviewed its answer to Qualcomm's grievance with accusations of its own.
That case accompanied a complaint with the US International Trade Commission seeking to ban the import of Apple iPhones that use competing Intel chips because of the alleged patent violations. But this week, it's updating those claims to include the iPhone X, which wasn't out when the legal battle first began. Two of those were related to Qualcomm's Snapdragon 800 and 820 processors, which powered Samsung phones and Google Pixel phones.
The patents the Cupertino tech giant is alleging were infringed are focused on the phone processor using only the minimum power needed, turning off parts of the processor when not in use and facilitating the processor's sleep and wake functions.
Apple at the time denied the claims and said that Qualcomm's patents were invalid, saying in a statement: "Qualcomm's illegal business practices are harming Apple and the entire industry". Apple has refuted the assertions that it breached battery life patents of Qualcomm and charged that Qualcomm's patents were worthless, a common step in such instances.
While the royalty fight works its way through the courts, Apple is not making payments to Qualcomm, and Apple has told its suppliers - particularly Foxconn - to withhold payment to Qualcomm as well. Samsung and Google are not named in Apple's counterclaims. In a related suit, Qualcomm sued the contract manufacturers that make Apple's phones, but Apple joined in to defend them.