Canadian Prime Minister Justin Trudeau has said he "deeply regretted" his actions in wearing a racist "brownface" at a private school gala in 2001.
Mr Trudeau said he "should have known better."
The 2001 yearbook image shows him with make-up with darkened his skin and hands at West Point Grey Academy in Vancouver.
It was obtained and published by Time Magazine, leading to the row.
Mr Trudeau is seeking re-election on October 21st.
Raheem Kassam tweeted: "This is one of the liberal establishment's greatest heroes - Justin Trudeau - wearing blackface:"
The Prime Minister is a former teacher who used to teach at the academy in Canada and the picture was taken when he was 29.
He was wearing a turban and robes with his face, neck and hands darkened by make-up.
The image is particularly embarrassing as he has made progressive policies a part of his mandate.
Speaking to journalists following the publication of the picture, he said he was dressed in an Aladdin costume at the Arabian Nights-themed gala.
"I take responsibility for my decision to do that. I shouldn't have done it," he said.
"I should have known better. It was something that I didn't think was racist at the time, but now I recognise it was something racist to do and I am deeply sorry."
Asked if there had been other occasions, he said he had also worn make-up while performing in a high school talent show.
An image from that second incident has since appeared on Twitter of Mr Trudeau when he was at Jean Brebeuf High School.
Robert Fife tweeted: "@JustinTrudeau in blackface at Jean Brebeuf high school. #cdnpoli #elxn43 #BreakingNews"
Brownface, yellowface or blackface refers to someone painting their face darker to resemble someone of a different skin colour.
It is a practice associated with minstrel performances and there have been a number of controversies involving celebrities, politicians and brands over recent years.
Mustafa Farooq, the executive director of the National Council of Canadian Muslims, said: "Seeing the prime minister in brownface/blackface is deeply saddening.
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"The wearing of brownface/blackface is reprehensible, and hearkens back to a history of racism and an Orientalist mythology which is unacceptable."
