GENEVA (Reuters) - An easing of international tensions with North Korea should lead to dialogue with Pyongyang to prevent continued “grave abuses” such as torture and political prison camps, a U.N. human rights investigator said on Wednesday.

Special Rapporteur on the situation of human rights in North Korea Tomas Ojea Quintana listens to a reporter's question during a news conference in Seoul, South Korea December 14, 2017. REUTERS/Kim Hong-Ji

Tomas Ojea Quintana, special rapporteur on human rights in the Democratic People’s Republic of Korea (DPRK), called on authorities there to release nine foreign nationals and resolve long-standing cases of abductions of South Koreans and Japanese.

Ojea Quintana, whose report to the Human Rights Council was based mainly on interviews with North Koreans living in South Korea and Japan, is not allowed into the reclusive country.

North Korea has never accepted the investigator’s mandate. “It is a dead document,” a North Korean diplomat, commenting on the latest report, told Reuters.

A 2014 U.N. commission of inquiry documented massive violations that it said may amount to crimes against humanity - including large prison camps, starvation and executions.

Ojea Quintana said that his information “indicates continuing patterns of serious violations made worse by a climate of political volatility and conflict rhetoric” over North Korea’s nuclear and ballistic missile programs.

Pyongyang has boasted of its plans to develop a nuclear-tipped missile capable of reaching the mainland United States. But fears of war eased last month, coinciding with North Korea’s participation in the Winter Olympics in the South Korean resort of Pyeongchang.

“It is important that the momentum that has been enabled by the Winter Olympics be used to discuss possibilities for bilateral technical support that may help tackle some of the urgent human rights challenges in the Democratic People’s Republic of Korea,” Ojea Quintana said.

The two Koreas should seize this momentum to resume family reunions for divided families - stalled since late 2015 - early this year as a “starting point for human rights dialogue”, he added.

The dialogue should include resolving “inconsistent accounts” on the case of 12 female North Korean restaurant workers in China who Pyongyang says were abducted in 2016, he said. South Korea, where they now live, say the women defected.

He urged China to halt its “forced repatriations” of North Koreans crossing the border, whom Beijing regards as economic migrants and not as people fleeing persecution, saying they faced the risk of torture on return.

South Korean President Moon Jae-in said on Wednesday sanctions on North Korea will not be eased for the sake of a summit between the two sides.

Referring to six South Korean nationals and three U.S. citizens detained in Pyongyang on charges of plotting hostile acts, Ojea Quintana said:

“The release of the remaining foreign detainees would help improve the country’s international stance and bring further appeasement to the political and security situation.”