German officials say that a series of sexual assaults and thefts that took place during New Year's Eve celebrations in the western city of Cologne were likely part of a coordinated effort by a criminal gang.
Police say about 1,000 men, most of "Arab or North African origin" had gathered near Cologne's main train station around midnight throwing fireworks. After police moved in to break up the revelry, smaller groups of men began surrounding women passing through the area, groping and harassing them and stealing their belongings.
A plainclothes police woman says she was among those attacked.
About 90 people have filed criminal complaints, including one report of a rape.
The DPA news agency reports that three suspects are being investigated.
Both Justice Minister Heiko Maas and Chancellor Angela Merkel have condemned the assaults and called for the perpetrators to be punished.
Police in the German cities of Hamburg and Stuttgart have said similar crimes were committed during New Year's Eve festivities, but to a lesser extent.
On Tuesday, hundreds of women demonstrated in front of Cologne's cathedral calling for more respect for women.
Although the nationalities and residency status of the perpetrators is unknown, the assaults have intensified the debate about Germany's immigration policies.
Some 1.1 million people registered as asylum seekers in Germany in 2015.