The London Police on Saturday arrested 52 persons, including several anti-monarchy protestors, during the coronation of King Charles III, BBC reported.

Charles III and his wife Camilla were crowned as the king and queen of the United Kingdom and the Commonwealth on Saturday. Charles III acceded to the throne after the death of his mother, Elizabeth II, on September 8.

On Saturday, human rights groups expressed concern about the arrests of the demonstrators. However, the city’s Metropolitan Police said that its officials acted proportionally under the law.

Commander Karen Findlay, who was leading the day’s operations, said that officers have a duty to intervene when “protest becomes criminal and may cause serious disruption”.

She added: “This depends on the context. The Coronation is a once in a generation event and that is a key consideration in our assessment.”

Among those arrested was Graham Smith, the head of anti-monarchy group Republic.

Late on Saturday, Smith said he was released from a police station. “Still waiting for my colleagues,” he said on Twitter.

Visuals on social media showed protestors holding up banners that read “Abolish the Monarchy” and “Not My King”.

Commenting on the arrests of the anti-monarchy protestors, Yasmine Ahmed, the head of the United Kingdom arm of Human Rights Watch, said: “These are scenes you’d expect to see in Russia not the UK.”

Climate group Just Stop Oil said that 13 demonstrators were arrested at the Mall in London and five others at Downing Street, according to the BBC. A spokesperson for the group said that the protestors only wanted to display flags and T-shirts

“This is a dystopian nightmare,” the spokesperson said.