The UN's top expert on the human rights situation in North Korea, Tomas Ojea Quintana, told the council in Geneva that increasing military tensions in the Asia-Pacific region had further isolated the Stalinist state.
And a separate group of experts, charged with exploring legal pathways to hold North Korea accountable for widespread rights abuses and crimes against humanity, reiterated calls to have the country referred to the International Criminal Court in the Hague.
Last March, North Korean Foreign Minister Ri Su Yong said the country would "no longer participate in international sessions singling out the human rights situation of (North Korea) for mere political attack," accusing the council of "politicisation, selectivity and double standards."
Quintana cautioned that escalating hostilities since North Korea resumed nuclear tests and missile launches in January 2016, including last week's launch of missiles toward the Sea of Japan (East Sea), "have put the few existing opportunities for cooperation and dialogue on human rights in jeopardy."
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"Should the investigation confirm the involvement of state actors, Mr Kim would be a victim of an extrajudicial killing, and measures would need to be taken to assign responsibilities and protect other persons from targeted killings," he said.
Previous UN reports have accused the country of committing human rights violations "without parallel in the contemporary world", including running a network of harsh prison camps holding up to 120,000 people.
The situation in the prison camps "remains a grave concern", Quintana said, pointing to the "risk of torture in detention, forced labour and summary execution."
A UN-mandated investigation in 2014 found that the country was responsible for abducting an estimated 200,000 foreign nationals from at least 12 countries.
Most of them were South Koreans left stranded after the 1950-1953 Korean War, but according to the inquiry, hundreds of others from around the world have been taken or have disappeared while visiting the country since then.
Diplomats today forcefully backed calls for Pyongyang and the perpetrators of rights violations in North Korea to be held accountable.