GENEVA, Oct 7 (Reuters) - North Korea"s most vulnerable risk starvation after it slipped deeper into isolation during the COVID-19 pandemic and U.N. sanctions imposed for its nuclear and missile programmes should be eased, a U.N. rights investigator said in report seen by Reuters. The worsening humanitarian situation could turn into a crisis and it is coinciding with a global "creeping apathy" about the plight of North Korea"s people, said Tomas Ojea Quintana, U.N. special rapporteur on human rights in the Democratic People"s Republic of Korea. "Sanctions imposed by the UN Security Council should be reviewed and eased when necessary to both facilitate humanitarian and lifesaving assistance and to enable the promotion of the right to an adequate standard of living of ordinary citizens," he said in a final report to the U.N. General Assembly, to be presented on Oct. 22. North Korea does not recognise Ojea Quintana"s mandate or cooperate with him and its mission in Geneva did not immediately respond to a request for comment. The government in Pyongyang does not take questions from foreign media.Leader Kim Jong Un in June said the food situation was "tense" because of natural disasters last year and acknowledged that citizens had faced sacrifices during the pandemic. In April, North Korean officials called a U.N. report on child malnutrition a "sheer lie". North Korea has not reported any COVID-19 cases and has imposed strict anti-virus measures, including border closures and domestic travel curbs. But many North Koreans relying on commercial activities along the border with China have lost their incomes, and that has been compounded by the impact of sanctions, Ojea Quintana said. "People’s access to food is a serious concern and the most vulnerable children and elderly are at risk of starvation," he said, adding that North Koreans "should not have to choose between the fear of hunger and the fear of COVID-19". "Essential medicines and medical supplies are in short supply and prices have increased several fold as they stopped coming in from China, and humanitarian organisations have been unable to bring in medicines and other supplies." Most diplomats and aid workers have left North Korea amid strict travel restrictions and a shortage of essential goods and health facilities, Ojea Quintana said. Progress in vaccination, women and children"s health and water and sanitation was eroding, he said. "The current worsening humanitarian situation could turn into a crisis and must be averted," he said. "CREEPING APATHY" He also voiced concern that growing challenges to obtaining information were "leading to a creeping apathy in global attention to the worsening human rights situation there". Ojea Quintana called for easing military tension on the divided peninsula and urged the United States and South Korea to "send clear signals" to revive diplomacy aimed at securing the North"s denuclearisation. In recent weeks, North Korea carried out a series of weapons tests including ballistic missiles and a cruise missile with potential nuclear capabilities. Ojea Quintana welcomed a pledge by U.S. President Joe Biden and South Korean President Moon Jae-in last May to work to improve North Korea"s rights situation. "In any possible upcoming peace negotiations, the Republic of Korea and the United States of America should secure commitments with measurable benchmarks ... to a meaningful process of engagement on human rights," he said. North Koreans are still detained in political prison camps, along with their families, while some have been released from labour training centres due to the unavailability of food and work, he said. The camps, known as kwanliso, the existence of which is denied by the state, can be qualified as constituting crimes against humanity, he said.