Taiwan's HTC mobile phone is displayed near an Apple Inc's iPhone and other models in a computer market in Taipei yesterday.

Apple Inc has sued Taiwan's HTC Corp, which makes touchscreen smartphones using Google software, accusing it of infringing 20 hardware and software patents related to the iPhone.

Even though the suit did not name Google Inc as a defendant, Apple's move was viewed by many analysts as proxy for an attack on the Internet company, whose Nexus One smartphone is manufactured by HTC.

"I think this is kind of an indirect lawsuit against Google," said Kaufman Bros analyst Shaw Wu.

Apple's suit was filed with both the United States International Trade Commission and the US District Court in Delaware on Tuesday, and seeks to prohibit HTC from selling, marketing or distributing infringing products in the US.

The complaint filed with the ITC cited Google's Nexus One, which was launched in January, and other HTC phones such as the Hero, Dream and myTouch - which run on Google's Android mobile operating system - as infringing products.

In a statement, a Google spokeswoman 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."