Apple, the company behind the iPhone, has filed a lawsuit against HTC over 20 patent infringements of the iPhone's user interface, underlying architecture and hardware.
Google launched its smartphone Nexus One at the beginning of the year, with HTC as its manufacturing partner.
A spokesman for the internet giant said: "We are not a party to this lawsuit. However, we stand behind our Android operating system and the partners who have helped us to develop it."
Apple launched the iPhone in 2007, followed in 2008 by the App store, which now offers more than 150,000 mobile apps across 90 countries.