Patrick Costello

Special for USA TODAY

BERLIN — German authorities are investigating alleged attacks on more than two dozen women at a music festival over the weekend that bear similarities to mass sexual assaults elsewhere in Germany during outdoor New Year's Eve gatherings.

Police said they arrested three Pakistani men, ages 28 to 31, in connection with the assaults, but they were later released, the Darmstadt Echo newspaper reported. Two of the three men have filed for asylum in Germany, according to the newspaper. Police would not say whether any charges have been filed.

It was not known if the two are among more than 1 million migrants who flooded Germany last year, most of them escaping war and poverty in the Middle East and Africa.

Saturday's incident took place during the Schlossgrabenfest music festival in Darmstadt, near Frankfurt. Twenty-six women told police they were surrounded by groups of up to 10 men, who harassed and touched them inappropriately, Darmstadt police told USA TODAY on Wednesday.

The four-day music festival attracts more than 100,000 people a day from across the country.

The allegations come five months after more than 1,000 women filed complaints with police that they were groped in Cologne and other German cities on New Year's Eve by men described as being of North African and Middle Eastern descent.

No one has been convicted of sexual assault in the New Year's Eve incidents, yet the news reports have stoked an already growing backlash in Germany against the influx of so many migrants. Chancellor Angela Merkel initially welcomed the newcomers but changed course after a public outcry.

In May, a 26-year-old Algerian man was the first to be tried in connection with the Cologne assaults, but was acquitted after the victim failed to identify him. He was convicted of an unrelated theft charge, according to the Cologne Regional Court. Cologne prosecutors have appealed the acquittal.

One other person has been charged with assault in Cologne, and that trial begins in July. All together, the Cologne incident has led to 15 trials for theft involving 18 suspects, nine of whom were convicted.

Cologne Police Chief Juergen Mathies told Focus magazine that it was more difficult to get an assault conviction because it's "easier to see (a theft) on the basis of video images."

He also said there was no evidence of organized crime in the assaults. Rather, he said, they bear a resemblance to attacks in the Middle East.

"Some of the perpetrators had made a plan to celebrate New Year's Eve in Cologne via social media, saying 'We'll go to Cologne — there will be a big party,'" he told the German news magazine. "This phenomenon of group sexual assaults — surrounding women and then abusing them — is a massive problem in Cairo, for example. The perpetrators were likely familiar with this behavior from their home countries."

The attacks have led German lawmakers to consider a new bill to make it easier to punish perpetrators of sexual assault. German rape victims can only get justice under current law if they can prove they physically resisted and said "no."

The bill — taken up by a parliamentary committee on Wednesday — allows for rape convictions when a victim withholds consent but does not physically fight back.

"There were unacceptable gaps in protection," said Justice Minister Heiko Maas in a statement. "It is high time ... (for a change). "We owe that to the victims."