North Korea's leaders should be brought before an international court for a litany of crimes against humanity that include exterminating, starving and enslaving its population, a U.N. team said Monday.
A hard-hitting report on the nuclear-armed totalitarian state also strongly criticised its denial of basic freedoms of thought, expression and religion, and its abduction of citizens of neighbouring South Korea and Japan.
"Systemic, widespread and gross human rights violations have been and are being committed by the Democratic People's Republic of Korea, its institutions and officials," said the report by the Commission of Inquiry on North Korea set up in March 2013 by the U.N. Human Rights Council.
"In many instances, the violations of human rights found by the commission constitute crimes against humanity. These are not mere excesses of the State; they are essential components of a political system that has moved far from the ideals on which it claims to be founded," the report said.
"The gravity, scale and nature of these violations revealed a State that does not have any parallel in the contemporary world."
North Korea refused to cooperate with the probe, which has claimed the evidence it has used is "fabricated" by "forces hostile" to the country.
Commission chair Michael Kirby wrote to North Korean leader Kim Jong-un -- the third ruler of the communist dynasty founded by his grandfather in 1948 -- to give him a last chance to put his country's side.
In a January 20 letter, reproduced in the report, Kirby told Kim he could face justice personally for the crimes committed by the system he runs.
"Any official of the Democratic People's Republic of Korea who commits, orders, solicits or aids and abets crimes against humanity incurs criminal responsibility by international law and must be held accountable under that law," Kirby wrote.
The report said options included the U.N. Security Council referring the country to the International Criminal Court or setting up an ad hoc tribunal.
The United States welcomed the report, saying it "clearly and unequivocally documents the brutal reality" of North Korea's abuses.
South Korea said the report attests to the "graveness" of the North Korean human rights situation. "It will help raise the international community's awareness," Seoul's Foreign Ministry said in a statement,
But Pyongyang's key ally China strongly opposed such a move, saying it would "not help resolve the human rights situation" and that "constructive dialogue" was the answer.
North Korea has long faced international sanctions over its atomic weapons programme, but activists said that justice for its rights record was long overdue.
"This has been six decades of human rights abuse in its most extreme and callous form," said Juliette de Rivero of Human Rights Watch.
Denied access to North Korea, the commission gathered evidence at hearings in South Korea and Japan with North Korean exiles -- dubbed "human scum" by the regime.
Most potential witnesses were afraid to testify even on a confidential basis because of fears of reprisals against relatives still in the country.
North Korea's crimes against humanity entail "extermination, murder, enslavement, torture, imprisonment, rape, forced abortions and other sexual violence, persecution on political, religious, racial and gender grounds, the forcible transfer of populations, the enforced disappearance of persons and the inhumane act of knowingly causing prolonged starvation," the report said.
It condemned a system of throwing generations of the same family into prison camps under guilt-by-association rules, given testimony from former guards, inmates and neighbours.
It estimated that there are 80,000-120,000 political prisoners in North Korea, a nation of 24 million people.
North Korean exiles in Geneva recounted the horrors they faced.
Kim Hyu Suk, born in 1962, said she was taken to a camp aged just 10 because her grandfather escaped from North Korea.
"During the 28 years that I lived in the camp, I lost my grandmother, my mother, my siblings, my children," she told reporters.
"The three generations of the regime in North Korea have been killing people through starvation while they are living well."
North Koreans' daily lives were marked by constant "surveillance, coercion, fear and punishment to preclude the expression of any dissent," the report said.
It estimated 200,000 people from other countries had been abducted by North Korea or disappeared after going there willingly.
Most were South Koreans stuck after the end of the 1950-1953 Korean War, and ethnic Koreans who arrived from Japan after 1959.
But hundreds of South Koreans, Japanese and nationals of countries including Thailand, Malaysia, Lebanon, Romania and France have also been pressganged as language teachers or even spouses.
North Korean defectors have also been kidnapped from countries including China, it said.
"These international enforced disappearances are unique in their intensity, scale and nature," the report said.