Six women reported being surrounded by "several dark-skinned men", who had robbed, groped and molested them, police said, adding that this was an unusually high number for Switzerland.
The statement mentioned the shocking rash of sexual assaults in several Germany cities also on New Year's Eve.
"It's a little bit similar," Zurich city police spokesman Marco Cortesi told AFP, adding though that the scale of the alleged attacks was "difficult to compare."
More than 120 criminal complaints have been filed in Cologne alone about robbery and sexual abuse, including two reported rapes by perpetrators who allegedly staged orchestrated attacks on revellers in the crowds.
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