OSLO/GENEVA (Reuters) - A campaign group seeking a global ban on nuclear arms won the Nobel Peace Prize on Friday, given the award by a Nobel Committee that cited the spread of weapons to North Korea and said the risk was growing of nuclear war.

The award to the International Campaign to Abolish Nuclear Weapons (ICAN) was unexpected, particularly in a year when the architects of the 2015 nuclear deal between world powers and Iran had been seen as favorites for achieving the sort of diplomatic breakthrough that has won the prize in the past. (Graphics on 'Nobel Laureates' - here)

Supporters described the award as a potential breakthrough for a global movement that has fought to ban nuclear arms from the day the first atomic bomb was dropped on the Japanese city of Hiroshima in August 1945.

ICAN’s Executive Director Beatrice Fihn told Reuters the group was elated. “This. Is. Surreal.” she later tweeted.

Asked if she had a message for North Korea’s Kim Jong-Un, who has tested nuclear arms in defiance of global pressure, and President Donald Trump, who has threatened to “totally destroy” North Korea to protect the United States and its allies, Fihn said both leaders need to know that the weapons are illegal.

“Nuclear weapons are illegal. Threatening to use nuclear weapons is illegal. Having nuclear weapons, possessing nuclear weapons, developing nuclear weapons, is illegal, and they need to stop,” she told Reuters.

Two days before her group won the prize, Fihn had tweeted that Trump was “a moron”. She told Reuters she had written this in jest, in the context of news reports that U.S. Secretary of State Rex Tillerson had used the same word to describe his boss. But she said Trump’s impulsive character illustrated the importance of banning nuclear arms for all countries.

“A man you can bait with a tweet seems to be taking irrational decisions very quickly and not listening to expertise, it just puts a spotlight on what do nuclear weapons really mean. There are no right hands for the wrong weapons,” she said.

ICAN describes itself as a coalition of grassroots non-government groups in more than 100 nations. It began in Australia and was officially launched in Vienna in 2007.

In her speech announcing the prize, Berit Reiss-Andersen, the leader of the Norwegian Nobel Committee, said the risk that nuclear weapons might be used was now “greater than it has been for a long time”.

“Some states are modernizing their nuclear arsenals, and there is a real danger that more countries will try to procure nuclear weapons, as exemplified by North Korea.”

The award was hailed by anti-nuclear campaigners around the world. “Now more than ever we need a world without nuclear weapons,” United Nations Secretary-General Antonio Guterres tweeted.

Mikiso Iwasa, an 88-year-old Hiroshima survivor, told Reuters the prize would help push the movement forward.

“It is wonderful we have this Nobel Peace-Prize winning movement. All of us need to join forces, think hard and walk forward together to turn this momentum into something even bigger,” he said.

NUCLEAR TENSIONS

The prize seeks to bolster the case for disarmament amid nuclear tensions between Washington and Pyongyang, as well as uncertainty over the fate of the 2015 deal between Iran and major powers to limit Tehran’s nuclear program.

The prize-giving committee made no mention of Iran in its award citation. It raised eyebrows with its decision to award the prize to an international campaign group with a relatively low profile, rather than recognize the Iran deal, a complex agreement hammered out over years of high-stakes diplomacy.

Slideshow ( 5 images )

“Norwegian Nobel Committee has its own ways, but the nuclear agreement with Iran achieved something real and would have deserved a prize,” tweeted Carl Bildt, a former Swedish prime minister who has held top posts as an international diplomat.

The Iran accord, which Trump has repeatedly called “the worst deal ever negotiated”, is seen as under particular threat this week. A senior administration official said on Thursday Trump is expected to “decertify” the pact, a step which could allow Congress to restore sanctions on Iran.

The committee may have been reluctant to reward the Iranian government for its role in the nuclear deal because the only Iranian winner so far, 2003 laureate Shirin Ebadi, a lawyer and human rights campaigner, is forced to live in exile.

“I think the committee has thought about the human rights situation in Iran. It would have been difficult to explain the prize even though it has a favorable view of the Iran deal,” Asle Sveen, a historian of the Nobel Peace Prize, told Reuters.

Slideshow ( 5 images )

The Norwegian Nobel Committee denied that giving the prize to an anti-nuclear group was intended either as a rebuke to Trump, or as a snub to the architects of the Iran nuclear deal.

“The Iran treaty is a positive development, a disarmament development that is positive, but the reason we mentioned North Korea (in our statement) is a reference to the threat that people actually feel,” Reiss-Andersen told Reuters. “Iran has not voiced recent threats to use nuclear weapons.”

ICAN has campaigned for a U.N. Treaty on the Prohibition of Nuclear Weapons, which was adopted by 122 nations in July this year.

That agreement is not signed by -- and would not apply to -- any of the states that already have nuclear arms, which include the five U.N. Security Council permanent members, the United States, Russia, China, Britain and France, as well as India, Pakistan and North Korea. Israel is also widely assumed to have nuclear weapons, although it neither confirms nor denies it.

Major allies of the declared nuclear powers also oppose the new treaty. Nevertheless, campaigners see it as a framework that would make it easier for countries that have nuclear arms to work toward eliminating them.

NATO member Norway congratulated ICAN but said it would not sign the treaty to ban nuclear weapons. The Nobel Peace Prize is awarded by a committee appointed by the Norwegian parliament.

“Norway will not support proposals in the UN that would weaken NATO’s role as a defence alliance,” Prime Minister Erna Solberg said.

Nuclear-armed nations, including the United States and Russia, back the U.N.’s 1968 nuclear non-proliferation treaty which sets limits on the spread of atomic weapons and has a long-term goal of nuclear disarmament.

“There is a strong logic in this peace prize,” said Dan Smith, director of the Stockholm International Peace Research Institute “It’s all about encouraging governments to do what they have promised to do in the non-proliferation treaty.”

($1 = 8.1556 Swedish crowns)