(CNN) - The surprise decision to award U.S. President Barack Obama the Nobel Peace Prize elicited swift reaction Friday, with some hailing the choice and others expressing astonishment and skepticism.
Praise came from Afghanistan's president, the Israeli defense minister and even a senior official from Hamas - the Palestinian militant group that controls Gaza. Yet an Egyptian human rights activist said he was "shocked" that Obama won. And the Internet hummed with a range of views.
Afghan President Hamid Karzai - whose U.S.-backed government is locked in warfare with Islamic militants - praised the choice.
"We congratulate, wholeheartedly, President Obama on the award of this prestigious award," said Karzai. "We recognize and commend President Obama's vision and leadership with a hope that peace and normalcy will return to Afghanistan and our region."
Yet Hisham Qasim, Egyptian democracy and human rights activist, said he was "shocked" Obama won.
"He has achieved nothing. He's stumbling. He hasn't achieved any of his promises and nothing is working. He promised to close Guantanamo and now that's not going to happen, and the Arab-Israeli conflict looks like it's going to get very nasty."
The Norwegian Nobel Committee said it gave the prize to Obama for his "efforts to strengthen international diplomacy," his "vision of and work for a world without nuclear weapons" and for inspiring hope and creating "a new climate in international politics."
Many questioned what Obama had accomplished to deserve the award.
Gideon Rachman, a foreign affairs columnist for The Financial Times, wrote an online blog under the headline "What did Obama do to win the Nobel Peace Prize?"
"I am a genuine admirer of Obama. And I am very pleased that George W Bush is no longer president. But I doubt that I am alone in wondering whether this award is slightly premature. It is hard to point to a single place where Obama's efforts have actually brought about peace – Gaza, Iran, Sri Lanka?
"While it is OK to give school children prizes for 'effort' – my kids get them all the time – I think international statesmen should probably be held to a higher standard," he wrote.
Obama has sought to make peace between Israel and the Palestinians, and officials from the Israeli government and Hamas sent congratulations and hope that the choice will help pave diplomatic ground.
Israeli Defense Minister Ehud Barak said he believes the prize "will strengthen President Barack Obama's capability to contribute to regional peace in the Middle East, and to an agreement between us and the Palestinians that will bring security, growth and prosperity to all the nations in the region."
Hamas official Ahmed Yousef also congratulated Obama, "though it is early for him to be awarded this prize."
"He reached out to the Muslim world in his Cairo speech and said many of the right things" and said "this is a man who thinks of achieving world peace"
He said he believes Obama represents a "new era in American politics," but thinks "the president has done nothing to push forward peace between Israeli and Palestinians" even though the "intention is there...it is an uphill battle with the Jewish lobby and Congress."
"We know he is somebody different from past leaders who supported Israel economically and militarily," Yousef said.
The Internet was alive with commentary from journalists, political leaders and ordinary people.
The winner of 1983's Nobel Peace Prize, anti-communist Polish leader Lech Walesa, was quoted in The Wall Street Journal as expressing surprise.
"Who, Obama? So fast? Too fast - he hasn't had the time to do anything yet," the paper's Web site quoted Walesa as saying.
One person expressed "sheer disbelief" that Obama had won, in a Twitter posting, saying the prize should have gone to a person such as Zimbabwe's Prime Minister Morgan Tsvangirai because "he stood up to a murderous dictator." Another person said she "seriously cannot believe they gave Obama the Nobel Peace Prize. Ridiculous."
Others had praise. One person wrote: "My president Just won the Nobel peace prize!!!! Go prez Obama."
Former Nobel peace laureates weighed in.
Kofi Annan, the former U.N. secretary general who won the peace prize in 2001, called the choice "unexpected but inspired."
"In an increasingly challenging and volatile world, President Obama has given a sense of hope and optimism to millions around the world" and "has shown that the only way forward is through genuine cooperation with other nations."
Former Finnish President Martti Ahtisaari, last year's Peace Prize laureate, said it was clear the Nobel committee wanted to encourage Obama on the issues he has been discussing on the world stage.
Wangari Muta Maathai, the Kenyan who won the 2004 Peace Prize, said Obama's win will help Africa move forward.
"I think it is extraordinary," she said. "It will be even greater inspiration for the world. He has shown how we can probably come together, work together in a cooperative way."
Former U.S. President Jimmy Carter, the 2002 peace prize laureate, called the selection "a bold statement of international support for his vision and commitment to peace and harmony in international relations." He said the move reflects the "hope" the Obama administration represents across the globe.
White House chief of staff Rahm Emanuel jokingly made reference to last week's awarding of Rio de Janeiro for the 2016 Olympics - which some viewed as a snub to the United States after Obama went to Copenhagen, Denmark to make a pitch for Chicago.
"It's clear Oslo beats Copenhagen any day of the week," he told CNN