By Matthew Henry and agencies

WISCONSIN, US: Apple Computers is counter-suing Creative Technology in the US, alleging the Singapore-based company has violated four iPod-related patents in its mp3 players.

Apple’s lawsuit was filed in the US District Court of Wisconsin on Monday – the same day Creative Technology initiated legal proceedings against Apple in California for a similar patent violation, related to Apple’s alleged use of Creative’s
patented user interface in its iPod players.

Apple has not commented publicly on what designs the four patent infringements relate too.

In a complaint lodged with the US International Trade Comission on Monday in conjunction with the court action, Creative demanded that all Apple iPod and iPod Nano players be removed from sale in the US due to their violation of its Zen Patent, which protects the user interface Creative developed for its original Nomad Jukebox player in 2000.

But Creative CEO, Sim Wong Hoo, has told the BBC that the company ultimately hopes to earn royalties from the lawsuit.