Nokia is replacing CEO Olli-Pekka Kallasvuo with Microsoft executive Stephen Elop as the world's top maker of mobile phones aims to regain lost ground in the fiercely competitive smart phone market.

The choice of a North American executive to lead a Finnish company reflects the increasing dominance of U.S. and Canadian companies in the evolution of the phone business.

Apple's iPhone has set the standard for today's smart phones, while Research In Motion's BlackBerry is the favorite of the corporate set. More recently, Google's Android software has emerged as the choice for phone makers that want to challenge the iPhone.

Analysts welcomed the choice of the 46-year-old Canadian, who has worked closely with Nokia at Microsoft and at Macromedia, developing software for Nokia phones. He has also held top posts at Juniper Networks and Adobe Systems. At Microsoft, he headed the business division, which makes Office software.

He takes over Sept. 21, Nokia said Friday.