The Taiwanese company, which has close links to internet giant Google, claims Apple has infringed five of its patents. The move follows legal action from Apple, which is claiming HTC broke 20 patents with its mobile phone technology.
Apple is also engaged in a bitter legal feud with the world’s biggest mobile phone manufacturer Nokia, also over patent infringement.
Meanwhile, in a major victory against internet piracy, file sharing software firm LimeWire has been found guilty of inducing copyright infringement.
The firm, which distributes P2P software that allows users to download each other’s music, could be liable for up to $150,000 (£100,000) for each proven case. With millions of files shared each day the ruling could spell the end of one of the biggest filesharing firms.
LimeWire argued it did not host or encourage any illegal activity but a US judge decided the software was geared towards the sharing of copyrighted material.