Brondby and Pogon Szczecin fans clashed outside the Brondby Stadium after their Europa Conference League tie on Thursday night.
The two sets of fans were seen throwing objects at each other and exchanging punches and kicks, as Danish cops used batons and dogs to separate them to a safe distance.
According to local media reports, one Pole was arrested.
Pogon Szczecin fans had also been involved in a battle with Danish cops inside the Brondby Stadium during the match.
Brondby were leading the game 4-0 in the 87th minute when the Polish side’s fans in the away end began breaking seats and shaking the fence separating them from the pitch. Police moved in and fighting broke out.