Smartphone maker High Tech Computer (HTC) on Wednesday defended itself against accusations of patent infringement by Apple, saying it develops its own technology.

The Taiwanese company, the world's largest maker of smartphones that use Google's Android mobile operating system, including the Nexus One, has been building mobile devices including smartphones for 13 years, "and so HTC is not only a mobile technology innovator, [we] also hold a large number of patents," the company said in a filing to the Taiwan Stock Exchange. 

HTC will work with the U.S. justice system to protect its own innovations and rights, it said, adding that it does not believe the Apple lawsuit poses a threat to its business in the short-term.

Apple filed a patent infringement lawsuit Tuesday in the U.S. against HTC, claiming that the Taiwanese company is infringing 20 Apple patents related to the iPhone user interface, underlying architecture and hardware.

The immediate impact of the suit was to send HTC stock down 2 percent, or NT$6.5, to close at NT$323.5 (US$10.10) on the Taiwan Stock Exchange.

Apple's filing includes smartphones from HTC that use Google's Android OS as well as some that run Microsoft's Windows Mobile OS. 

Technology companies often file infringement lawsuits against each other, sometimes for legitimate claims and sometimes as a ploy to harm a rival's business. Smartphone vendors have been actively filing lawsuits against each other.

Nokia, the world's largest mobile phone vendor, sued Apple last October over the alleged infringement of 10 patents. Apple turned around and sued Nokia over claims of its own.