Canada is withdrawing from a UN nuclear disarmament conference in protest of North Korea's presidency of the body, the Canadian foreign minister has said.
In Ottawa on Monday, John Baird said it was "absurd" that North Korea had taken the rotating presidency of the Conference on Disarmament.
The presidency of the 65-member-nation conference rotates every four weeks.
In May, a UN panel accused North Korea of exporting nuclear and missile technology in violation of sanctions.
"North Korea is simply not a credible chair of a disarmament body," Mr Baird said in a statement.
"The regime is a major proliferator of nuclear weapons and its non-compliance with its disarmament obligations goes against the fundamental principles of this committee. This undermines the integrity of both the disarmament framework and the UN. Canada will not be party to that."
North Korea's ascension this month to the presidency of the 32-year-old UN Conference on Disarmament was dictated by the body's rules.
Under those, the presiding country holds that position for four weeks before it rotates to another country.
Canada will resume its role on the 65-member body on 19 August, when North Korea's turn as president ends.
The US has indicated it did not plan to boycott the conference.
The May UN report said North Korea employed a number of "masking techniques" to export weapons to Iran, Syria and Burma in violation of a UN ban.
It said the country mislabeled shipping container contents, falsified information about the destinations of goods and used "multiple layers of intermediaries, shell companies, and financial institutions".
The Conference on Disarmament is the UN's sole forum for negotiating multilateral arms control and non-proliferation treaties.
Other non-proliferation efforts have been undertaken on Iran by the so-called P5+1 group of nations (US, Russia,China, France, Britain and Germany), and on North Korea through six-party talks involving regional powers.