Leaked video of Sanna Marin dancing exuberantly has sparked controversy in Finland, with critics of the 36-year-old prime minister accusing her of inappropriate behaviour and supporters praising her style and defending her right to party. The video, first published by the tabloid Iltalehti and compiled from several since-deleted Instagram clips, shows Finland’s youngest ever leader dancing enthusiastically and drinking with friends, apparently in a private apartment. Other guests identified in the footage, which Marin on Thursday acknowledged was genuine and said was filmed “a few weeks ago”, include two well-known TV and radio hosts, a social media influencer, a YouTuber, a stylist, the singer Alma and an MP from Marin’s Social Democratic party. Marin told reporters she was “upset” that the clips, which she knew were being filmed but had believed would remain private, had been leaked. “I spent the evening with my friends, partied, even in a rowdy way, danced and sang,” she said. Finnish media alleged a voice in the background could be heard shouting “the flour gang”, supposedly a reference to cocaine or amphetamines. Marin and other commentators denied this was the term used, however, and she said she did not know what it meant. “I myself have not used drugs, nor anything other than alcohol,” she said. “Nor have I been in such a situation that I would have seen or known others [using drugs]. I was dancing, singing, partying … hugging my friends, doing totally legal things.” She said she had nothing “to conceal or hide” and was determined to continue to be “the same person as I have been until now … I have free time that I spend with my friends. I’m pretty sure that’s the same as many people my age”. The video triggered an instant backlash. Mikko Kärnä, a Centre party MP, tweeted that the prime minister should take a drugs test and publish the result. “The people are entitled to expect this from their prime minister,” he said. Iltalehti columnist Lauri Nurmi said the situation was “serious” for Marin. “It goes without saying that the prime minister of Finland cannot be present at parties where narcotics prohibited by the criminal code are openly consumed,” he said. Marin responded that she was willing to take a drugs test if necessary. “I have nothing to hide,” she repeated to reporters later on Thursday. “I haven’t used drugs, so it’s not a problem to go for a tests. But I also think it’s quite unusual that something like this is required.” Some social media users described her as incompetent and irresponsible. Others, however, defended Marin’s right to party. A senior Social Democrat MP, Antti Lindtman, said she had “a lot of sympathy and support”. There was “dancing at a private event”, he said. “I see nothing to write home about.” Marin, who was the world’s youngest prime minister in 2019, has won widespread praise for her handling of the Covid pandemic, in which Finland fared better than most EU member states, and of the fallout from Russia’s invasion of Ukraine. Finland won independence from Russia only in 1917 and shares an 810-mile border with its powerful eastern neighbour, whose forces it twice repelled during the second world war, but Marin this year piloted its path out of decades of neutrality and non-alignment to apply for Nato membership. Her personal style has also won her admirers outside Finland. Commenting on a photograph of Marin heading to Helsinki’s Flow festival in a second-hand glittery dress, Germany’s Bild tabloid this week described her as “relaxed, modern and confident”. Marin is a member of “the cool generation”, the paper said, “the most important politician in her country, leading it through one of the most dangerous crises of her time – and who still finds time to celebrate”. This is not, however, the first time her partying has got her into trouble. In December she was forced to apologise on Facebook when she danced at a Helsinki nightclub until 4am after coming into contact with her foreign minister, who had tested positive for Covid. She said she had initially been told she did not need to self-isolate because she had been fully vaccinated, but later missed a text message advising her to do so because it had been sent to her government telephone, which she had left at home. Critics claimed failing to double-check the guidelines was proof of poor judgment, while the decision to leave her official phone at home was a potential national security breach. Marin later said she was “very sorry” for the lapse.