The mostly young women said they were encircled and groped by groups of men on Saturday night in ways that recalled a spate of mob attacks at chaotic New Year’s festivities in Cologne.
Police said they were investigating whether the perpetrators also robbed the women in the latest attacks at a four-day open air music festival in the western city of Darmstadt.
Initially three women had filed charges, leading to the arrests of the three men, Pakistani asylum seekers aged 28 to 31, and another 15 women have come forward since.
Police said they were searching for another two or three men and said in a statement that “the women have reported that they appeared to be men from the South Asia region”.
The Cologne attacks — committed in a crowd of mostly Arabic and North African men — appalled Germany and sharpened public concern about the arrival of over one million mostly asylum seekers last year, most from the Middle East.
In the inflamed debate, far-right groups railed against “sex jihadists” and “rapefugees”.