Motorola has filed a new lawsuit against Apple in the US over claims the firm is infringing on six of its patents in use in both the iPhone 4S and its iCloud service.
The action comes with the backing of Google, which is in the process of buying Motorola for $12.5bn. A clause in the acquisition deal states that Motorola must not undertake any legal action without the firm's approval.
V3 contacted Motorola and Apple for comment on the action but had received no reply at the time of the publication.
A Google spokesman declined to comment, but added that the company and Motorola are still operating separately.
Patent analyst Florian Mueller explained the six patents Motorola has included in its new action are already being used in a separate case against older iPhone products.
"Motorola would have preferred to add the iPhone 4S and the iCloud to the list of technologies accused in an action that started in late 2010," he explained in a blog post.
"However, that litigation is already far along, with a trial scheduled for this summer, and the judge rejected Motorola's supplemental infringement contentions as untimely but said [it] would be free to accuse those technologies in a separate lawsuit."
Mueller explained that while the resubmission of an existing complaint was interesting, it was the backing of Google that most notable.
"It's certainly not the same kind of aggressive escalation as a lawsuit over a new set of patents would have been, but this shows that Motorola continues to fight hard," he said.
"The fact that Google signs off on an additional lawsuit at this stage, as opposed to waiting for its purchase of [Motorola] to close, also says something."
Motorola has already had legal successes against Apple, winning a case in Germany before Christmas that gives it the right to ban the import of the firms iPad and iPhone devices to the region.
It also managed to see off a challenge in the US from Apple earlier this month.
Dan Worth is the news editor for V3 having first joined the site as a reporter in November 2009. He specialises in a raft of areas including fixed and mobile telecoms, data protection, social media and government IT. Before joining V3 Dan covered communications technology, data handling and resilience in the emergency services sector on the BAPCO Journal.