Microsoft and South Korea's LG Electronics this morning said they had signed a preliminary agreement on strategic collaboration in mobile technology.
"The agreement ensures continued strategic collaboration in R&D, marketing, applications, and services in the field of converged mobile devices," LG said in a statement.
"Both companies will continue to define and align their mobile strategies through annual top management meeting."
The agreement was signed during Microsoft CEO Steve Ballmer's trip to South Korea.
Meanwhile larger home rival Samsung Electronics on the same day announced the launch of the domestic version of the Omnia touch screen handset model, based on Microsoft's Windows Mobile 6.1 operating system.
The model will be available from mid-November under an exclusive deal with SK Telecom, Samsung said.
Microsoft is hoping its Windows Mobile operating system can continue to challenge Symbian, a platform backed by the world's top mobile phone maker Nokia and used in two-thirds of smartphones - mobile handsets with computer-like capabilities.
Blackberry-maker Research in Motion and Apple Inc's iPhone are also growing threats to Symbian, while several manufacturers are planning or have started to roll out smartphones based on Google's Android software.
Both LG and Samsung are members of the Symbian Foundation and are also developing models based on Android.
"These are not new deals, but rather a way for South Korean makers to reinforce existing alliances," said Greg Roh, an analyst at Korea Investment & Securities, about the Microsoft-related announcements.
"Competition is getting more and more fierce in the smartphone segment, and South Korean makers have some weaknesses on Symbian platforms, so it is understandable that they would broaden their alliances."