HTC, the Taiwan-based maker of Google’s Nexus One cellphone, says it plans to mount an aggressive defense against a patent-infringement suit brought by Apple.

Apple filed suits early this month alleging HTC devices including the Nexus One violated 20 of its patents. The suit didn’t name Google, but was seen by many analysts as an attack by proxy on the Internet search giant, the latest outburst in an increasingly tense relationship between the two Silicon Valley heavyweights.

HTC, which makes several phones aside from the Nexus One that run on Google’s Android software, offered no details about how or when it would respond.