Taiwan's leading smartphone maker HTC said it would appeal a ruling by a United States trade body which found that it had infringed two patents held by US giant Apple.
Apple filed a complaint against HTC in March 2010 with the US International Trade Commission (ITC) accusing the Taiwanese firm of violating ten patents related to the iPhone.
A preliminary finding on Friday reportedly said that HTC had violated two of the patents. HTC maintains none of the ten were infringed.
"We are highly confident we have a strong case for the ITC appeals process and are fully prepared to defend ourselves using all means possible," said HTC general counsel Grace Lei in a statement, on Saturday.
"We strongly believe we have alternate solutions in place for the issues raised by Apple. We look forward to resolving this case," she said, without elaborating.
The ITC has already ruled in a separate case that Apple infringed on patents held by HTC subsidiary S3 Graphics, according to the Taiwanese company.
As the legal battle between the rivals escalated, Apple filed a new compliant against HTC with the ITC on Monday involving patents related to iPads and iPhones. It has also lodged a suit against HTC in a US District Court in Delaware.
HTC touts its own brand of smartphones and also makes handsets for a number of leading US companies, including the Nexus One unveiled by Apple rival Google.
Patent lawsuits are a regular occurrence among technology giants. Apple is currently being sued by Nokia for patent infringement, and has fired back a countersuit against the Finnish mobile phone giant.
Last week Apple also hit back at an infringement claim by Samsung, calling for the South Korean company to be investigated.