Updated at 11:15 a.m. Eastern.
President Barack Obama won the 2009 Nobel Peace Prize on Friday for "his extraordinary efforts to strengthen international diplomacy and cooperation between peoples," the Norwegian Nobel Committee said, citing his outreach to the Muslim world and attempts to curb nuclear proliferation.
The committee said Mr. Obama's efforts to promote a "global response to global challenges" cemented their decision.
CBS News White House correspondent Peter Maer reports that White House press secretary Robert Gibbs emailed a one-word reaction to the news Friday morning: "Wow."
The White House was clearly just as shocked by the announcment as the reporters gathered in Oslo, reports Maer.
It was Gibbs who eventually told Mr. Obama he had won the prestigious Prize - about 45 minutes after the announcement at 6 a.m. EDT, reports CBS News senior White House correspondent Bill Plante.
The committee praised Mr. Obama's effort to create a "new international climate" of diplomacy.
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CBS News White House correspondent Mark Knoller reports that Mr. Obama is only the third U.S. President to win the Nobel Peace Prize while still in office. Theodore Roosevelt won it in 1906 and Woodrow Wilson in 1919.
Former President Jimmy Carter also won the prize in 2002, adds Knoller, but that was more than two decades after he left office.
Defending their surprising decision, the committee chairman said they sought not just to reward the winner of the Nobel Peace Prize, but to "enhance" the recipient's actions - to promote peace.
"We do hope that this can contribute a little bit to enhance what he is trying to do."
"It is a clear statement to the world that we want to advocate and promote," the efforts undertaken by Mr. Obama.
"Only very rarely has a person to the same extent as Obama captured the world's attention and given its people hope for a better future," Thorbjoern Jagland, chairman of the Nobel Committee said. "In the past year Obama has been a key person for important initiatives in the U.N. for nuclear disarmament and to set a completely new agenda for the Muslim world and East-West relations."
He added that the committee endorsed "Obama's appeal that 'Now is the time for all of us to take our share of responsibility for a global response to global challenges."'
Mr. Obama's name had been mentioned in speculation before the award but many Nobel watchers believed it was too early to award the president.
"The Prize has to be seen as a political statement by the Nobel committee - meant to hail the change in U.S. policy represented by President Obama's approach to foreign policy as opposed to that of his predecessor George W. Bush," says Knoller, who notes that Mr. Obama took office less than 10 days before the Feb. 1 deadline for Nobel Prize nominations.
"This is a Prize meant as an expression of hope that President Obama's speeches and policy statements will translate into actual accomplishments," adds Knoller. "The Prize is honoring an expression of aspirations for peace, rather the achievement of it."
That decision by the Nobel Committee, however, is a caluclated risk. Knoller says the members may be discredited for awarding the Prize for aspirations, rather than accomplishments.
"I don't think anybody expected this," CBS News chief Washington correspondent and "Face the Nation" host Bob Schieffer said on Friday's "Early Show". In his mind, the prize decision was more of a commentary on the previous administration than the current U.S. President.
"It's almost as if they're saying, 'We're giving you this prize for winning the election,'" said Schieffer.
The committee said it attached special importance to Mr. Obama's vision of and work for a world without nuclear weapons.
"Obama has as president created a new climate in international politics. Multilateral diplomacy has regained a central position, with emphasis on the role that the United Nations and other international institutions can play."
In his 1895 will, Alfred Nobel stipulated that the peace prize should go "to the person who shall have done the most or the best work for fraternity between the nations and the abolition or reduction of standing armies and the formation and spreading of peace congresses."
Unlike the other Nobel Prizes, which are awarded by Swedish institutions, he said the peace prize should be given out by a five-member committee elected by the Norwegian Parliament. Sweden and Norway were united under the same crown at the time of Nobel's death.
The committee has taken a wide interpretation of Nobel's guidelines, expanding the prize beyond peace mediation to include efforts to combat poverty, disease and climate change.