SEATTLE (Reuters) - Microsoft Corp sued Motorola Inc, alleging patent infringement on the handset maker’s line of Android phones, in the latest development in a web of legal actions in the evolving smartphone business.

Signage for Motorola is displayed outside their office building in Tempe, Arizona October 29, 2009. REUTERS/Joshua Lott

Microsoft, the world’s largest software company, charged that former ally Motorola infringed nine of its patents in the Android-based smartphones, which run on software built by Google Inc.

Microsoft makes its own Windows phone software, which it charges handset makers to use in their phones. Motorola, like some rivals, has shifted toward Google’s free Android as a more attractive option, straining the relationship between the two companies.

The suits come 10 days before Microsoft launches the new version of its mobile software, which it hopes will win back market share from Apple Inc’s iPhone and Google.

The patents in question relate to synchronizing e-mail, calendars and contacts, scheduling meetings and notifying applications of changes in signal strength and battery power, Microsoft said in a statement.

A Motorola spokeswoman said the company has not yet received a copy of the suit, but based on its strong intellectual property portfolio, plans to “vigorously defend itself.”

Google said it was disappointed in Microsoft’s move, which it claimed would threaten innovation in the sector. “While we are not a party to this lawsuit, we stand behind the Android platform and the partners who have helped us to develop it,” the company said in an e-mailed statement.

The suit is the latest in a complicated series of legal actions between various phone makers and software firms over who owns patents to the technology used in smartphones, kicked off by Nokia suing Apple last year, and Apple subsequently suing handset maker HTC Corp. Oracle Corp has also sued Google over Android software.

“Our action today merely seeks to ensure respect for our intellectual property rights infringed by Android devices,” said Horacio Gutierrez, deputy general counsel in charge of Microsoft’s intellectual property, in a blog post on the company’s website. “Judging by the recent actions by Apple and Oracle, we are not alone in this respect.”

Microsoft said it filed its actions against Motorola at the International Trade Commission and in federal court in Seattle.

The case is 2:10-cv-01577 Microsoft Corporation v. Motorola Inc, filed in the U.S. District Court for the Western District of Washington.