The number of sexual offence complaints almost quadrupled at this year's carnival in Cologne, despite heightened security aimed at preventing a repeat of the mass assaults that marred the city's New Year celebrations.

A total of 66 complaints for sexual insults or aggression were lodged between last Thursday, when the carnival got underway, and Wednesday morning. The previous year there were 18 such reports, police said.

Police also revealed they had to break up a mass brawl between asylum seekers and carnival goers when one of the refugees allegedly began to grope a teenage girl.

The violent incident, which left three people hospitalised, occurred at the end of this year's Cologne Carnival, which police have now confirmed resulted in more crimes.

Cologne police (pictured) had to break up a mass punch-up between asylum seekers and carnival goers when one of the refugees began to grope a teenage girl

Police officers arrest a young man in Cologne. Police from Cologne and neighbouring Leverkusen said there had been 673 crimes reported at the carnival, of which 55 were of a sexual nature

Outlining the incidents, police from Cologne and neighbouring Leverkusen said there had been 673 crimes reported.

In addition, 432 people ended up being taken into custody. Police said all these figures represented an increase on the year before.

The violent confrontation which ended carnival festivities this week happened when a group of asylum seekers clashed with carnival-goers.

Police said a knife had been used and that three people were hospitalised as a result of the attack, which was started by an alleged sexual assault on a young woman by one of the refugees.

They said that one of the asylum seekers, believed to be a 27-year-old from North Africa, had groped the 19-year-old and that the carnival-goers had stepped in to protect her.

The Cologne and Leverkusen police force said officers calmed the situation down and made arrests.

They also announced that they ordered bars and clubs in the Bahnhofstrasse area of Leverkusen to close in order to prevent the violence from spreading and going out of control.