OSLO President Barack Obama won the 2009 Nobel Peace Prize on Friday in a stunning decision designed to encourage his initiatives to reduce nuclear arms, ease tensions with the Muslim world and stress diplomacy and cooperation rather than unilateralism.

Nobel observers were shocked by the unexpected choice so early in the Obama presidency, which began less than two weeks before the Feb. 1 nomination deadline.

White House press secretary Robert Gibbs said Obama woke up to the news a little before 6 a.m. EDT. The White House had no immediate comment on the announcement, which took the administration by surprise.

The Norwegian Nobel Committee decided not to inform Obama before the announcement because it didn't want to wake him up, committee chairman Thorbjoern Jagland said.