The Nexus One / David Sandison

Apple said today it filed a lawsuit against HTC Corp, saying that the maker of the Hero phone infringed on 20 Apple patents related to the iPhone's user interface and hardware.

Apple, which popularized touchscreen phones when it launched iPhone in 2007, said it filed the suit at the same time with the U.S. International Trade Commission and the U.S. District Court in Delaware.

The suit also claims HTC, which makes touchscreen phones - many of which are based on Google Inc Android operating system - infringed patents related to the iPhone.

The claim is the latest scrape over ownership of the underlying technology for smartphones - handsets that play video and music, take pictures and send e-mail - which are increasing in popularity among consumers.

For example, Eastman Kodak Co in January filed a complaint with the ITC Apple's iPhone and Research in Motion Ltd's BlackBerry camera phones infringe the photography company's patents.

Nokia, the world's top mobile phone maker, also sued Apple in January for alleged patent violations. The dispute, potentially involving hundreds of millions of dollars in annual royalties, reflects the shifting balance of power in the mobile industry as cellphones morph into handheld computers that can play video games and surf the Web.