A wartime president being honored for peace, Barack Obama said Thursday that criticism of his Nobel prize as premature might recede if he advances goals such as a nuclear-free world and tackling climate change. But, he added, proving doubters wrong is "not really my concern." "If I'm not successful, then all the praise in the world won't disguise that fact," said Obama from this chilly, damp Nordic capital where he is picking up his Nobel Peace Prize. The Nobel committee announced Obama had won the peace prize in October when he wasn't even nine months on the job, recognizing his aspirations to reshape the way the U.S. deals with the world much more than his actual achievements. "It was a great surprise to me," Obama said after meeting with Norwegian Prime Minister Jens Stoltenberg. "I have no doubt that there are others who may be more deserving." Obama announced just days before coming here to formally accept it that he is ordering 30,000 more U.S. troops into war in Afghanistan. This has not gone unnoticed, with peace activists staging a protest to coincide with the Nobel ceremonies. The president's motorcade arrived at Oslo's high-rise government complex to a few dozen anti-war protesters gathered behind wire fences nearby. Dressed in black hoods and waving banners, the demonstrators banged drums and chanted anti-war slogans. "The Afghan people are paying the price," some shouted. Greenpeace and anti-war activists planned larger demonstrations later that were expected to draw several thousand people. Protesters have plastered posters around the city, featuring an Obama campaign poster altered with skepticism to say, "Change?" Stoltenberg defended Obama as a Nobel laureate. "I cannot think about anyone else who has done more for peace during the last year than Barack Obama," Stoltenberg said at Obama's side. "I think it's a very bold and important decision." In awarding the prize to Obama, the Nobel panel cited his call for a world free of nuclear weapons, for a more engaged U.S. role in combating global warming, for his support of the United Nations and multilateral diplomacy and for broadly capturing the attention of the world and giving its people "hope." But the list of Nobel peace laureates over the last 100 years includes transformative figures and giants on the world stage. They include heroes of the president, such as the Rev. Martin Luther King Jr., Nelson Mandela and others he has long admired, like George Marshall, who launched a postwar recovery plan for Europe. So the choice of Obama was such a surprise, and derided so loudly by some critics as premature, that the Nobel committee took the unusual step of defending itself. Obama seemed Thursday to try to distance himself from that debate. "On a whole host of initiatives that I've put forward this year, some of which are beginning to bear fruit, the goal is not to win a popularity contest or to win an award - even one as esteemed as the Nobel Peace Prize," he said. "The goal is to advance American interests." Obama's first stop in Oslo was the Norwegian Nobel Institute, where the Nobel committee meets to decide who gets the prestigious prize. After signing the guest book at the Institute with a lengthy passage, Obama told reporters he had penned thanks to the committee members and noted the pictures of former winners filling the wall, saying that many gave "voice to the voiceless." Obama singled out King's 1964 prize, which he said increased his stature in the world and had a "galvanizing effect" on the civil rights leader's cause at home. The president is joining the list of winners under such odd circumstances that he will make a point of it himself. Obama's Nobel speech - a tradition billed as the winner's lecture for the world - will explore his thinking about war, security and the pursuit of peace. He is likely to spell out the role of American leadership and the responsibilities of all nations. Obama was considering lots of ideas for the speech and had been expected to winnow them into a final draft on his flight. There will be plenty of splashy ceremony, too. In the evening, Obama is expected to wave to a torchlight procession from his hotel balcony and stroll with Norwegian royalty to a dinner banquet. He will offer comments a second time there and cap his brisk jaunt to Europe. The president and his wife, Michelle, arrived here in the morning after an overnight flight from Washington, coming off Air Force One holding hands and smiling. Obama was due back in Washington by midday Friday. Obama's quick trip reflects a White House that sees little value in trumpeting an honor for peace just nine days after Obama announced he was sending more troops off to war. Asked if Obama was excited about the award, national security aide and speechwriter Ben Rhodes responded, "I think he feels as if it places a responsibility upon him." "It's the company that you keep as a Nobel laureate that I think makes the deepest impression upon him," said Rhodes, who was helping craft the president's speech. "That kind of adds an extra obligation to essentially extend the legacy." The Nobel honor comes with a $1.4 million prize. The White House says Obama will give that to charities but has not yet decided which ones.