Nokia has finalised an agreement with Accenture to develop the Symbian mobile OS as the company switches its smartphone strategy to Windows Phone 7.

About 2,800 Nokia employees in China, Finland, India, the UK and the US will be transferred to Accenture in early October. Accenture will provide software development and support for Symbian through 2016, Nokia said. Some employees who are transferred will be retrained.

Nokia announced the deal with Accenture in April amid dramatic company changes, including the decision in February to use Microsoft's Windows Phone OS.

Under the agreement, Accenture will support Symbian while also developing mobility software and services around Windows Phone. Accenture will also work with Avanade, a company that is majority-owned by Accenture and works with Microsoft technologies, to provide other services to Nokia.

Nokia's smartphone sales began to slide in 2007 with the introduction of Apple's iPhone and Google's Android OS. The move to Windows Phone came after Stephen Elop, former president of Microsoft's business software group, was named CEO of Nokia in September 2010.

Nokia said in April that it expects to eliminate another 4,000 jobs in Denmark, Finland and the UK through the end of 2012.