The Finnish Prime Minister, Sanna Marin, is facing a backlash after being seen partying in a leaked video.
In the footage, thought to be taken from social media, she and friends including Finnish celebrities are seen dancing and singing.
She has faced criticism from opposition parties, with one leader demanding she takes a drug test.
Ms. Marin, 36, denied taking drugs, saying she only drank alcohol and just partied "in a boisterous way".
Finland’s Prime Minister @MarinSanna is in the headlines after a video of her partying was leaked today.— Visegrád 24 (@visegrad24) August 17, 2022
She has previously been criticized for attending too many music festivals & spending too much on partying instead of ruling.
The critics say it’s not fitting for a PM. pic.twitter.com/FbOhdTeEGw
Formerly the world's youngest head of government - a title now held by Chilean President Gabriel Boric - Ms. Marin makes no secret of partying and has often been photographed at music festivals.
Last year she apologized for going clubbing after coming into close contact with a Covid-19 case.
Just last week, Ms. Marin was dubbed the "coolest prime minister in the world" by the German news outlet Bild.
Commenting on the video on Thursday, she said she knew she was being filmed but was upset that the video had become public.
"I danced, sang, and partied - perfectly legal things. And I've never been in a situation where I've seen or known of others [using drugs]," she added.
Opposition party leader, Riikka Purra, called for Ms. Marin to take a voluntary drug test, saying there was a "shadow of a doubt" hanging over the prime minister.
And MP Mikko Karna, a member of the Centre Party who serve in Ms. Marin's coalition government, tweeted that "it would be wise" for her to "voluntarily undergo a drugs test".
Ms. Marin appeared open to the suggestion, telling reporters that she had "not used drugs" and had "no problem taking tests".
"I have a family life, I have a work life and I have free time to spend with my friends. Pretty much the same as many people my age," Ms. Marin said.
She added that she felt no need to change her behavior. "I am going to be exactly the same person as I have been until now and I hope that it will be accepted," the prime minister added.
There has been widespread reporting on the video in Finnish media - which justified the use of the footage as being in the public interest.
But other opposition party politicians have criticized both the prime minister and the media for talking about partying - instead of more important domestic problems.
Ms. Marin has been in power since December 2019 and retains the support of her party.
"The reaction is very typical on all things Marin: polarised," Finnish political journalist and media commentator Robert Sundman told the BBC.
"There are people saying that it is normal for a woman her age to have fun with her friends and people who are shocked.
"But at least until now, one thing is sure: the previous party pictures have not - at least significantly - affected the popularity of her or her party."
Mr. Sundman said there has been lots of attention over her friendship with Finnish celebrities, which he says is a significant departure from previous prime ministers.
Last week, the prime minister won plaudits for her style after being pictured with the influencer and photographer Janita Autio, who also appeared in the video, at a music festival in Helsinki.