North Korea's state television on Saturday showed leader Kim Jong-un making his first public appearance after a weeks-long absence that fuelled speculation about his health and possible death. The footage showed Mr Kim walking, waving to cheering workers and cutting a ribbon at what state media said was the opening of a fertiliser plant on Friday in Sunchon, north of Pyongyang. At one point he sat in front of a sign that described the event as a factory opening ceremony for May 1, 2020. "All the participants broke into thunderous cheers of 'hurrah!'" when he appeared, the Korean Central News Agency (KCNA) said. He also inspected the facility and was "briefed about the production processes", the report said. Mr Kim "said with deep emotion" that his grandfather Kim Il-sung and father Kim Jong-il "would be greatly pleased if they heard the news that the modern phosphatic fertiliser factory has been built," KCNA said. Mr Kim has not made a public appearance since presiding over a Workers' Party politburo meeting on April 11, and the following day state media reported on him inspecting fighter jets at an air defence unit. Conjecture about his health grew after he failed to attend celebrations of the birth anniversary of his grandfather Kim Il-sung, the North's founder, on April 15 – the most important day in the country's political calendar. Rumours that he was ill or incapacitated raised speculation about who might take charge of the rogue nuclear state, which severely limits access to information about its activities and leadership. South Korea's unification ministry reacted to Saturday's report by saying "groundless" speculation about Mr Kim had caused "unnecessary confusion", calling for more careful consideration in future. Officials in Seoul have downplayed reports the North Korean leader might be seriously ill or dead, while US President Donald Trump suggested earlier this week that Washington believed Mr Kim to be alive. A top security adviser to South Korea's President Moon Jae-in said less than a week ago that Mr Kim was "alive and well" and had been staying in Wonsan – a resort town in the east of North Korea – since April 13. Daily NK, an online media outlet run mostly by North Korean defectors, has reported that Mr Kim was undergoing treatment after a cardiovascular procedure last month. Citing an unidentified source inside the country, it said Mr Kim, who is in his mid-30s, had needed urgent treatment because of heavy smoking, obesity and fatigue. Soon afterwards, CNN reported that Washington was "monitoring intelligence" that Mr Kim was in "grave danger" after undergoing surgery, quoting what it said was an anonymous US official. Mr Kim's previous absences from the public eye also prompted speculation about his health. In 2014, he was not seen for nearly six weeks before reappearing with a cane. Days later, the South's spy agency said he had undergone surgery to remove a cyst from his ankle. The North is extremely secretive, and doubly so about its leadership. Mr Kim's father and predecessor Kim Jong-il had been dead for two days before anyone outside the innermost circles of North Korean leadership was any the wiser.