Apple filed a $1 billion lawsuit against Qualcomm on Friday, a few days after the US Federal Trade Commission sued the chip maker for antitrust violations.

Apple alleged that Qualcomm "has unfairly insisted on charging royalties for technologies they have nothing to do with." The iPhone maker said that Qualcomm was overcharging and is refusing to pay around $1 billion worth of rebates, which were reportedly withheld because of Apple's talks with the Korean Fair Trade Commission (KFTC), South Korea's antitrust regulator, according to Reuters.

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The Tim Cook-led firm also said that even though Qualcomm is just one of the many contributors to its basic cellular standards, the chip maker collects at least five time higher than all other cellular patent licensors agreed with combined.

Apple also said that the more it integrated new unique features on its products, the bigger the amount Qualcomm collected from them. For instance, if it upgrades the iPhone's memory from 128 GB to 256 GB, Qualcomm would allegedly charge higher royalties, the Forbes noted.

"If that were not enough, Qualcomm then attempted to extort Apple into changing its responses and providing false information to the KFTC in exchange for Qualcomm's release of those payments to Apple. Apple refused," the Cupertino, California-based firm said.

In response, Qualcomm's General Counsel Don Rosenberg described Apple's allegations as "baseless," saying that Apple has been "encouraging regulatory attacks on Qualcomm" across different jurisdictions across the world.

"We welcome the opportunity to have these meritless claims heard in court where we will be entitled to full discovery of Apple's practices and a robust examination of the merits," Rosenberg said.

The lawsuit, which was filed in US District Court for the Southern District of California, came just a few days after the US charged Qualcomm of imposing "onerous" supply and licensing terms on other smartphone makers.

Qualcomm is a major supplier of both Apple and Samsung Electronics Ltd. for "modern" chips that allow smartphones to connect to wireless networks. Together, the two giants account for an estimated 40 percent of the San Diego-based firm's $23.5 billion revenue, according to its latest fiscal year.