Apple announced on Tuesday that it had filed a lawsuit against HTC, maker of the Nexus One smartphone from Google, accusing the Taiwan company of infringing on 20 iPhone patents.
"We can sit by and watch competitors steal our patented inventions, or we can do something about it," Apple chief executive Steve Jobs said in a statement.
"We've decided to do something about it. We think competition is healthy, but competitors should create their own original technology, not steal ours," Jobs said.
Apple accused HTC of infringing on 20 Apple patents related to the "user interface, underlying architecture and hardware" of the iPhone.
The company, based in Cupertino, California, said the lawsuit was filed in a US District Court in the state of Delaware and with the US International Trade Commission.
Apple has sold more than 40 million iPhones since introducing the smartphone in 2007.
HTC makes handsets for a number of leading companies and is the manufacturer of the Nexus One unveiled by Apple rival Google in January.
Apple is currently being sued by Nokia for patent infringement and has countersued the Finnish mobile phone giant.