HTC has strengthened its legal cases against Apple after acquiring nine patents from Google last week.
The Taiwanese manufacturer has made amendments to two lawsuits against Apple, adding five patents to the International Trade Commission (ITC) and US District Court of Delaware filings.
The patents alleged to have been infringed range from technology used to display characters on the phone keypad, to the over-the-air upgrading of software.
HTC has also claimed in the Delaware filing that Apple's entire product and service range, including MacBook, iMac, Mac Mini, iPhone, iPod, iPad, MobileMe, iCloud and iTunes, are infringing the patents.
Patent specialist Florian Mueller pointed out that it was always possible that Google would help Android device manufacturers to fight Apple.
"I'm sure Apple always knew that Google might give patents to embattled Android device makers. That didn't prevent Apple from enforcing its rights in the first place. It won't make Apple back down now. There's too much at stake for that, and it's easier to file lawsuits than to win them," he said on the Foss Patents blog.
"I wouldn't be surprised to see Apple file a motion to dismiss in order to require HTC to be a little more specific. Federal lawsuits don't have to be nearly as specific as ITC complaints, but this lack of specificity is not necessarily accepted."
HTC said in a statement to V3 that the company will continue to protect its patented inventions against infringement from Apple.
"We believe that we have an obligation to protect our business, our industry partners and our customers, who love using our products," said Grace Lei, general counsel at HTC.
Apple responded with an equally succinct statement: "We think competition is healthy, but competitors should create their own original technology, not steal ours."
Google has been building up its patent portfolio to defend Android against lawsuits, including the $12.5bn acquisition of Motorola Mobility.
Meanwhile, some good news emerged for Apple after VoIP company ICloud Communications dropped its lawsuit regarding the use of the term 'iCloud'.
ICloud Communications had accused Apple of "knowingly and willfully treading on the trademark rights of others", but it appears that some sort of compromise has been reached, although Apple declined to comment on the matter.
Apple reportedly paid $4.5m to secure the iCloud.com domain shortly before it announced the service at WWDC 2011.
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