German state interior minister Ralf Jaeger has said migrants were almost exclusively responsible for the attacks on women in Cologne on New Year's Eve.
More than 100 women reported being threatened, robbed or molested during the city's celebrations.
The minister's comments come amid reports a group of Pakistanis and a Syrian were violently attacked by about 20 unknown assailants on Sunday in the city.
The German interior minister has said the fact that people of foreign descent were behind much of the violence in Cologne on new year's eve should not be kept quiet but neither should it lead people to general suspicion towards all refugees and migrants.
Thomas de Maiziere described the violence as "completely unacceptable" and said it was urgent that new tougher legislation be agreed to punish the perpetrators, saying Germany could not afford long, divisive debates about changes to the law.
The German Chancellor wants increased powers to block foreigners from being granted asylum if they have any sort of criminal record.
Around 400 people gathered in Cologne to demonstrate against violence against women following a wave of assaults on New Year's Eve.
Authorities in Cologne are holding crisis talks on Tuesday after a string of sexual assaults by large gangs of men.