GENEVA, Feb 17(Reuters) - United Nations human rights investigators on Monday issued a damning report cataloguing massive human rights violations in North Korea that they said amount to crimes of humanity which should be brought to the International Criminal Court (ICC).

The 372-page report is the result of a year-long investigation marked by unprecedented public testimony by defectors at hearings held in South Korea, Japan, Britain and the United States.

Kim Jong-un may be personally responsible for crimes against humanity, top U.N. investigator Michael Kirby said in a Jan. 20 letter to the North Korean leader that accompanies the report.

Here are some excepts from the report, to be debated by the U.N. Human Rights Council in Geneva on March 17:

SCOPE OF CRIMES

"Systematic, widespread and gross human rights violations have been and are being committed by the Democratic People's Republic of Korea, its institutions and officials. In many instances, the violations of human rights found by the commission constitute crimes against humanity.

"The gravity, scale and nature of these violations reveal a State that does not have any parallel in the contemporary world," the report said.

"A number of long-standing and ongoing patterns of systematic and widespread violations which were documented by the commission, meet the high threshold required for proof of crimes against humanity in international law. The perpetrators enjoy immunity.

"The key to the political system is the vast political and security apparatus that strategically uses surveillance, coercion, fear and punishment to preclude the expression of any dissent."

CHINA'S ROLE

"Persons who are forcibly repatriated from China are commonly subjected to torture, arbitrary detention, summary execution, forced abortion and other forms of sexual violence.

China should "respect the principle of non-refoulement and accordingly abstain from forcibly repatriating any persons to the Democratic People's Republic of Korea".

"China should raise with the Supreme Leader of the Democratic People's Republic of Korea and other high-level authorities the issues of abductions, the infanticide of children entitled to Chinese nationality, forced abortions imposed on repatriated women and other human rights violations that target persons repatriated from China.

The report includes a Dec. 16 letter from chairman Kirby to China's ambassador in Geneva, Wu Haitao, urging him to "caution relevant officials that such conduct on their part could amount to the aiding and abetting (of) crimes against humanity".

Wu's reply, dated Dec. 30, said North Koreans enter China illegally for economic reasons and some are engaged in "criminal acts such as theft, robbery, illegal harvesting". Some North Koreans repeatedly enter China illegally, demonstrating that the allegation that repatriated citizens face torture is "not true", Wu's letter said.

The Commission of Inquiry cited estimates that there are 10,000 to 25,000 children born of Chinese fathers and North Korean mothers. "The status of most of these children appears to be effectively stateless, as the Chinese families have been discouraged from registering such children because of the illegal status of their mothers," it said.

North Korean agents "appear to be operating on Chinese territory and attempting to gather information about DPRK citizens and persons supporting them. On some occasions, they appear even to have abducted DPRK citizens and at least one national of the ROK (Republic of Korea)".

TORTURE CHAMBERS AND PRISON CAMPS

"Suspects of major political wrongs may find themselves in a detention interrogation centre anywhere from a few days to six months or more," it said.

"Torture is an established feature of the interrogation process", it said, citing testimony about a "torture chamber" at a detention facility of the State Security Department equipped with a water tank, shackles used to hang suspects upside down, and long needles driven underneath a suspect's fingernails.

"Many suspects die at interrogation detention centres as a result of torture, deliberate starvation or illnesses developed or aggravated by the terrible living conditions."

"If they are not executed immediately, persons held accountable for major political wrongs are forcibly disappeared to political prison camps that officially do not exist. Most victims are incarcerated for life, without chance of leaving the camps alive."

"The limited information that seeps out from the secret camps also creates a spectre of fear among the general population in the DPRK, creating a powerful deterrent against any future challenges to the political system."

"Four large prison camps are known to exist in the DPRK today," it said, adding that there may be additional ones and that there were 12 camps or more in the past.

"Over time, the system has been consolidated. Some camps were closed down and the remaining inmates transferred to other sites, which were expanded.

Sources including human rights groups concur there has been a drop in the political prison camp population over the last few years, but this may be partly due to an "extremely high rate of deaths in custody," due to starvation and neglect, arduous force labour, disease and executions, the U.N. report said.

The Korea Institute for National Unification estimates 80,000 to 120,000 people are detained in political prison camps today, based on recent satellite imagery and first-hand testimony, the report said. The activist group Committee on Human Rights in North Korea put the figure at 80,000 to 130,000.

DEPRIVATION OF FOOD AND STARVATION

A 1995 food crisis sparked by floods and the collapse of support and hard currency from the Soviet Union led to famine.

"The State has used food as a means of control over the population .... The State has also used deliberate starvation as a means of control and punishment in detention facilities. This has resulted in the deaths of many political and ordinary prisoners.

"Military spending - predominantly on hardware and the development of weapons systems and the nuclear programme - has always been prioritised, even during periods of mass starvation."

"The commission finds that decisions, actions and omissions by the State and its leadership caused the death of at least hundreds of thousands of people and inflicted permanent physical and psychological injuries on those who survived.

"Hunger and malnutrition continue to be widespread. Deaths from starvation continue to be reported.

"The commission is concerned that structural issues, including laws and policies that violate the right to adequate food and freedom from hunger, remain in place, which could lead to the recurrence of mass starvation.

"In his 2014 New Year's message, Supreme Leader Kim Jong-un called for 'decisive improvement in guidance and management of economic projects'. However, measures for agricultural reform and opening the economy were not mentioned in the speech."

LUXURY GOODS AND "PARALLEL FUNDS"

North Korea "continues allocating a significant amount of the state's resources for the purchase and importation of luxury goods", the report said.

Such imports are in violation of Security Council sanctions and have included high-quality cognac and whiskey and equipment for a 1,000 person cinema, it said. There have been attempts to import Mercedes-Benz vehicles, high-end musical recording equipment and dozens of pianos, it said.

"Luxury good expenditure by the DPRK rose to $645.8 million in 2012. Reportedly, this was a sharp increase from the average of $300 million a year under Kim Jong-il," it said, citing a British newspaper report in October 2013.

North Korean authorities also engage in legal and illegal activities to earn foreign currency, channelling it into "parallel funds" outside of the regular state budget, it said.

"They are kept a the personal disposal of the Supreme Leader and used to cover personal expenses of the Supreme Leader, his family and other elites surrounding him, as well as other politically sensitive expenditures," it said.

Revenue from criminal activity including drugs has been estimated at up to $500 million a year in 2008, amounting to a third of North Korea's annual exports at the time, it said.

A former North Korean official, not identified in the report, provided information on the "illegal activities of DPRK embassies around the world. They were engaged in activities such as the illegal sale of alcohol in Islamic countries or the internationally prohibited trafficking of ivory from African countries to China," the report said.

(Reporting by Stephanie Nebehay)