HTC is using patents newly assigned to it by Google to sue Apple, according to a Bloomberg report.

The Taiwanese smartphone pioneer has apparently amended existing complaints made with the US International Trade Commission and a regional court in Delaware, as well as filing another suit in the state. In each case, it alleges infringements of patents assigned to it by Google last week.

Apparently, the nine patents which have been transferred originate from Motorola, Openwave Systems and Palm, with Google having taken ownership of them less than twelve months ago. Bloomberg said that Google has not commented on why it made the move now, but that it will strengthen HTC’s defence against Apple.

Previously, there were question marks over the extent to which Google would – or could – assist Android licensees in their various legal actions, due to the relative weakness of its mobile patent portfolio. Indeed, its planned acquisition of Motorola Mobility was explicitly linked with a strategy to bolster its intellectual property holdings – although some observers noted that this has not stopped Motorola itself from being sued.

The move also indicates that Google sees HTC as an important partner moving forward, as one of the leading suppliers of Android devices. This will help smooth concerns that it may favour Motorola once it takes ownership of the business, and shifts from being a platform supplier to integrated hardware and software vendor.

HTC and Apple have made numerous complaints to US watchdogs about patent infringements. In addition to the patents assigned by Google, it has also acquired intellectual property from ADC Telecommunications, and inked a deal to buy graphics technology firm S3 Graphics, which is also involved in a patent spat with Apple.