The Danish prime minister was assaulted on Friday evening in Copenhagen, her office has said.
Mette Frederiksen was “beaten” by a man in Kultorvet public square in the centre of the Danish capital, local media reported.
The prime minister’s office said she was left “shocked” following the attack. It was unclear if she had been injured.
Danish police arrested a suspect and confirmed the incident to Jyllands-Posten, the local newspaper, but made no further comment.
Ms Frederiksen has recently been campaigning with her party ahead of the European Parliament elections on Sunday.
The elections have been dominated by a rise in the hard-Right.
Magnus Heunicke, the environment minister, sent his support, calling the attack “ugly and unacceptable”.
“Denmark’s prime minister Mette Frederiksen was today assaulted and beaten by a man on Kultorvet in Copenhagen,” he said.
“Mette is naturally shocked by the attack. I must say that it shakes all of us who are close to her.
“Something like this must not happen in our beautiful, safe and free country. We all have a responsibility to look after each other and the values our country is built on. The police have arrested a man for the assault.”