The Danish capital has not seen hooliganism on Sunday's level since the 2000 UEFA Cup final between English club Arsenal and Turkish Galatasaray was held at Copenhagen's Parken stadium, reports DR.
Episodes of violence and attacks on riot police marred post-match scenes, with fireworks also let off in streets near the stadium, deputy inspector Henrik Møller Jakobsen of Copenhagen Police told the broadcaster.
“We have ascertained that around 20 of our colleagues were hit by thrown objects, including stones, bottles and other things,” Jakobsen said.
Of the 14 arrests, four were made prior to the match.
“Troublemakers have the ability to make a high-risk match more than live up to its name. To start with, keeping them separated went fine, but stones were thrown at police both inside and outside of Parken… between 15 and 20 of my colleagues have been hit,” Jakobsen told TV2.
The unrest is reported to have occurred mainly after the match, which finished 3-1 to FC Copenhagen.
A video posted on Twitter by TV2 journalist and social media editor Kaare Sørensen showed police clashing with Brøndby fans inside the stadium after the match ended.
Video: Politiet i Parken trækker stave mod Brøndby-fans pic.twitter.com/aTIqpSJ3U7— Kaare Sørensen (@KaareSorensen) May 25, 2017
Some of the Brøndby fans tore out seats and threw them at police, according to the TV2 report.
Jyllands-Posten sports editor Troels Henriksen reported flares being thrown into the Brøndby section by FC Copenhagen fans.
“It is typical after a game like this for the crowd to divide into separate groups, and then a lot of incidents occur. Some have also fought internally,” Jakobsen told DR.
Fans were arrested and charged with disorder at locations around the city including the Rådhuspladsen main square, the Trianglen junction in the Østerbro neighbourhood near the stadium, and on the Lyngbyvej and Haraldsgade roads, according to reports.
Only seven fans were arrested throughout the entire DBU Pokal cup tournament last season, reports DR.
“Our assessment is that this is the most serious match for Copenhagen Police since we had Galatasaray and Arsenal, which was a European match,” Jakobsen said.
Violence after the 2000 European final included fights between rival fans at Rådhuspladsen and chairs and tables from cafés being thrown.
Jakobsen told TV2 that police succeeded in keeping fans of the two clubs separated after Sunday's match.
Matches between Copenhagen rivals Brøndby and FC Copenhagen are known to be some of the most tense in Danish domestic football.
Flares lit during the DBU Cup final Sunday. Photo: Ida Marie Odgaard/Scanpix
“There's not doubt that years of experience show that Brøndby and FCK don't like each other. That's why we usually have a heavy presence at these games… Maybe there was extra antagonism today because it was a cup final,” said Jakobsen.