Legal action is being taken by iPhone manufacturer Apple against Taiwanese rival HTC over 20 alleged patent violations in the firm's new Google-branded smartphone.
Touchscreen mobile phone technology which HTC utilises is one of the elements under attack from Apple, although the iPhone itself was not the first mobile to bring touch sensitivity to the marketplace.
Apple Chief Executive Officer Steve Jobs said: "We think competition is healthy, but competitors should create their own original technology, not steal ours."
According to industry insiders, the final straw came when HTC implemented the pinch-to-zoom functionality in the Nexus One's web browser software with an update in February.
Various US courts have been presented with Apple's suit, including the International Trade Commission (ITC). Involving the ITC will probably be part of an attempt by Apple to prevent the importing of HTC products, if the suit goes in its favour.
Independent observers have reacted with surprise to Apple's latest move, with many thinking it unusual for the Californian firm to use patents offensively against rivals.
Apple has never fired the first shot in a legal dispute with another business before now, but it is well equipped for a court battle over patent infringements given its history of sparring with Nokia.