Bloomberg news reports that Nokia Oyj is close to announce a partnership with Microsoft to use the Windows Phone 7 operating system on Nokia phones. This enables both companies to leverage on each other’s strength to challenge Google and Apple in the mobile war.

Nokia Chief Executive Officer Stephen Elop will unveil a new strategy for Nokia at an event in London tomorrow and everything will be clear if Nokia will continue with Symbian and MeeGo

Nokia Chief Executive Officer Stephen Elop has held talks with Microsoft CEO Steve Ballmer about putting Microsoft’s mobile operating system on Nokia phones, said the person, who asked not to be identified because the discussions were private. Elop also held talks with Google CEO Eric Schmidt about using Google’s Android software, the person said. Those discussions are unlikely to lead to an alliance, according to another person familiar with the matter.

Some investors and analysts say the steps may be too little, too late for the world’s largest mobile-phone maker.

“Very few companies regain their leadership once they’ve lost it,” said Hakim Kriout, a fund manager at Grigsby & Associates in New York, who holds Nokia shares. “It’s a very difficult thing to do because their demise tends to originate from a combination of problems rather than one or two issues.”