US President Barack Obama accepted his Nobel Peace Prize at a ceremony in Oslo, and claimed that war was sometimes the only option.

Obama also addressed the controversy that was sparked by his nomination for the peace prize on October 9.

"In part, this is because I am at the beginning, and not the end, of my labors on the world stage," he said.

Obama expressed understanding that critics were irked by the fact he was the president of a country that was caught up in two wars, in Iraq and Afghanistan.

However, he stressed that one of these wars was winding down and that the other conflict (Afghanistan) had not been sought by America.

He used his speech to justify the use of force against certain opponents.

"A non-violent movement could not have halted Hitler's armies. Negotiations cannot convince al Qaeda's leaders to lay down their arms," Obama said, adding "to say that force is sometimes necessary is not a call to cynicism – it is a recognition of history."

"The instruments of war do have a role to play in preserving the peace, and yet this truth must coexist with another - that no matter how justified, war promises human tragedy.

Among the other themes that Obama addressed were the role of NATO in peacekeeping and the need for nuclear disarmament.

He spoke about not ignoring dangers posed by Iran and North Korea and ensuring there were consequences for those responsible for human rights violations in Darfur, Congo and Burma.

Obama, who was present with wife Michelle, went on to talk about the use of religion to justify war. It was not the first time this had been done, he said, citing the "cruelty of the crusades."

"Distortion" of religion

"Most dangerously we see it in the way that religion is used to justify the murder of innocents by those who have distorted and defiled the great religion of Islam and who attacked my country from Afghanistan."

"Such a warped view of religion is not just incompatible with the concept of peace but the purpose of faith - for the one rule that lies at the heart of every major religion is that we do unto other what we would have them do unto us."

Obama finished on the theme of hope, the absence of which he said could "rot societies."

Defense of decision

Thursday's award ceremony at Oslo's city hall had begun with the Nobel Committee delivering a staunch defense of its decision in October to honor US President Barack Obama with the prestigious peace prize.

The five-member committee had justified its decision by saying that Obama had introduced a new era of engagement and multilateralism in foreign policy. It added that this deserved to be encouraged - a clear reference to widespread global opposition to the policies of the previous US administration under George W. Bush.

Thorbjoern Jagland, the chairman of the Nobel Committee, stressed that Obama's policy deserved to be supported.

"Many have argued that the prize comes too early, but history can tell us a great deal about lost opportunities," Jagland said.

"It is now, today, that we have the opportunity to support President Obama's ideas. This year's prize is indeed a call to action for all of us," he added.

Nobel Peace Prize as an incentive

Obama, who is only the third US president after Theodore Roosevelt and Woodrow Wilson to receive the prize, was humble in assessing the Nobel Committee's choice.

"I have no doubt there are others who may be more deserving," Obama said at a joint press conference with Norwegian Prime Minister Jens Stoltenberg ahead of the award ceremony.

"My task here is to continue on the path that I believe is not only important for America, but important for lasting peace and security in the world," he added.

He cited several initiatives launched during his first year in office, ranging from climate change, a world without nuclear weapons, and stabilizing countries like Afghanistan.

"If I am successful in those tasks, then hopefully some of the criticism will subside," adding that "if I am not successful, then all the praise and the awards in the world won't disguise that fact."

One of Obama's biggest tests will be the outcome of NATO's mission in Afghanistan, and the president used the press conference to reiterate his pledge that the US would in 2011 begin to "transfer responsibility" to Afghan forces as part of an exit strategy.

Unearned laurels?

Critics have questioned the decision to award a peace prize to a "war president" who recently announced the deployment of an additional 30,000 troops to Afghanistan.

Norwegian peace groups and anti-nuclear organizations staged demonstrations outside the award ceremony. Outside the Nobel committee offices, protestors held up a banner reading "Obama you won the prize, now earn it."

In the United States, a Quinnipiac University survey of more than 2,300 registered voters published on Tuesday showed that by a wide margin of 66 to 26 percent, Americans thought Obama did not deserve the Nobel Peace Prize.

The prize comes with an 18-carat gold medal, the diploma and a cheque worth 10 million Swedish crowns ($1.41 million). Obama has already pledged to donate the funds to charity.

nk/rc/AFP/Reuters/dpa/AP

Editor: Ranty Islam