North Korea is suspected of having resumed operations at its plutonium production facility, a US institute monitoring the site said Friday. Commercial satellite imagery from January 22 showed “a water plume originating from the cooling water outlet of the reactor, an indication that the reactor is very likely operating,” the US-Korea Institute of Johns Hopkins University said on its 38 North website, referring to the Yongbyon Nuclear Scientific Research Centre. A river running along the nuclear site that is usually frozen at this time of the year was not frozen where the water plume mixes with the river, the institute said. North Korea is keen to improve its nuclear weapons including those to be mounted on intercontinental ballistic missiles to counter what Pyongyang claims is the threat from the United States. North Korean elite are turning against leader Kim, top defector claims “Without being able to measure the water temperature rise or water flow from the reactor, it is impossible to estimate at what power level the reactor is running, although it may be considerable,” the institute added. According to the institute, the nuclear facility at Yongbyon has been stalled since the second half of 2015. The United States, Japan and South Korea have been on alert for possible provocations by North Korea such as missile launches and nuclear tests. At the same time, Pyongyang has appealed to UN Secretary General Antonio Guterres to help North Koreans it claims are being held against their will in South Korea to go home, according to a letter obtained by Kyodo News on Friday. In the letter to the UN chief, Ambassador Ja Song-nam cited the case of Kim Ryon-hui, who left North Korea in 2011 to seek medical treatment in China and now claims to be trapped in South Korea. “I would like to take this opportunity to urge for an appropriate action by your office for an immediate repatriation of Kim Ryon-hui,” Ja said in the letter. He branded Kim’s case as an example of “the enticed group abduction” of the North’s nationals by authorities in the South. Kim claimed she was convinced to seek out short-term employment in South Korea to help pay the costs of the medical treatment she received in China, according to media reports. Kim told Kyodo News in a 2015 interview in South Korea that she had made a mistake and was now without a passport, having been required to turn it over, and is unable to leave the country. North Korean newspaper saves a special place for report of Trump’s inauguration In his letter, Ja claims that such acts constitute a “crime against humanity” and “will be a touchstone testing the true stand of the UN for the promotion and protection of human rights”. North Korean Counsellor Ri Song-chol told Kyodo that a previous letter last May to then UN chief Ban Ki-moon, whom Guterres replaced in January, went unanswered. “This is a real human rights violation case but they (the United Nations) do not touch this issue,” Ri said. “We have high expectations for the secretary general to solve this issue as an urgent and emergency human rights issue.” The United Nations has confirmed receipt of the letter but did not offer any further details. North Korea’s human rights record was the focus of discussion in the UN Security Council for the third year in a row last December. The UN General Assembly also adopted last month a Japan- and European Union-led resolution rebuking the North for its continued rights abuses for the 12th year in a row.