The Norwegian Nobel Committee, warning of a rising risk of nuclear war and the spread of weapons to North Korea, has awarded the 2017 Nobel Peace Prize to a little-known campaign group seeking a global ban on nuclear arms.
The award for the International Campaign to Abolish Nuclear Weapons was unexpected, particularly in a year when the architects of the 2015 nuclear deal between international powers and Iran had been seen as favourites for achieving the sort of diplomatic breakthrough that has won the prize in the past.
Still, supporters saw it 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 said the group was elated.
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, she 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."
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 on Friday.
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.
"We live in a world where the risk of nuclear weapons being used is greater than it has been for a long time," said Berit Reiss-Andersen, the leader of the Norwegian Nobel Committee, in her speech announcing the prize.
"Some states are modernising 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.
ICAN has campaigned for a UN 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 UN 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.