Danish Prime Minister Mette Frederiksen was on Friday "hit" by a man on a Copenhagen square, her office said, with EU chiefs quickly condemning the attack.

The Danish prime minister's office said in a statement that Frederiksen was "shocked by the incident," but did not provide further details.

"Prime Minister Mette Frederiksen was hit by a man Friday evening on Kultorvet in Copenhagen. The man was subsequently arrested," the statement said.

The incident comes on the heels of a spate of attacks on politicians from across the political spectrum at work or on the campaign trail in Germany ahead of this week's EU elections.

On May 15, Slovak Prime Minister Robert Fico was shot four times at close range as he greeted supporters after a government meeting in the central town of Handlova.

Fico, who survived the assassination attempt, was taken to a hospital in a nearby city after the shooting, where he underwent two lengthy surgeries.

EU chief Charles Michel and European Parliament President Roberta Metsola on Friday slammed the attack on Frederiksen.

Metsola urged the Danish head of government to "keep strong," while adding in a post to X that "violence has no place in politics."

Michel in turn said he was "outraged by the assault."

"I strongly condemn this cowardly act of aggression," the European Council president said in a separate post to X.

Copenhagen police confirmed that an incident involving the prime minister had occurred but did not provide further details.

"We have one person arrested in the case, which we are now investigating. At this time, we have no further comments or remarks on the case," police said in a statement on X.

"I must say that it shakes all of us who are close to her," Danish Environment Minister Magnus Heunicke said in a post to social media.

"Something like this must not happen in our beautiful, safe and free country," he said. (AFP)