The International Campaign to Abolish Nuclear Weapons has won the Nobel Peace Prize.
The world's nuclear powers must begin "serious negotiations" aimed at disarmament, the Nobel committee said.
"This year's Peace Prize is also a call upon these states to initiate serious negotiations with a view to the gradual, balanced and carefully monitored elimination of the almost 15,000 nuclear weapons in the world," said Norway's Nobel committee president Berit Reiss-Andersen.
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," added Ms Reiss-Andersen.
In July, 122 nations adopted a UN Treaty on the Prohibition of Nuclear Weapons, but nuclear-armed states including the United States, Russia, China, Britain and France stayed out of the talks.
Watch the very moment the 2017 Nobel Peace Prize is announced! #NobelPrize pic.twitter.com/H0AtcRU7tn— The Nobel Prize (@NobelPrize) October 6, 2017
The Nobel prize seeks to bolster the case of disarmament amid nuclear tensions between the US and North Korea and uncertainty over the fate of a 2015 deal between Iran and major powers to limit Tehran's nuclear programme.
US President Donald Trump has called the Iran agreement the "worst deal ever negotiated" and a senior administration official said today that Mr Trump is expected to announce that he will decertify the landmark pact.
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Among the nominees for this year's peace prize was a foundation established by an Irish priest to free Filipino children and women from sex traffickers.
The People's Recovery, Empowerment and Development Assistance Foundation (PREDA) organisation, was founded by the Columban missionary, Fr Shay Cullen, who is from Dublin.
ICAN will receive their prize, consisting of a gold medal, a diploma, and a cheque for around €950,000, in Oslo on 10 December.