GETTY Immigrants have sexually assaulted a number of women in a German city in Cologne copycat attack

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Police said so far only four women have filed complaints after the incidents in Essen late on Friday - but htta number is "only the tip of the iceberg." Now women who may have been attacked at the Essen Original city party have been offered a confidential hotline by officers to contact them. The police presence at the festival was beefed up over the weekend as a result of the sexual assaults.

All said that men came up to them in groups, danced around them, harassed and groped them. This mirrored the attacks in Cologne on December 31 2015 when mobs of North African migrants assaulted hundreds of women in attacks which served to turn Germany against the open-door refugee policy of Chancellor Angela Merkel. Despite defending her record in a long interview on Saturday with the BILD newspaper, the Chancellor is braced for a beating at the hustings on Sunday when the anti-immigration Alternative for Germany (AfD) party is set to defeat her own CDU conservatives in a regional election in her home state.

Police said the Essen victims were attacked in three parts of the city by North African men in groups of four and six "who drove their victims into corners and groped them all over. Most of the abusers are still being hunted but police apprehended several lone suspects shortly after the complaints were made. Two 16-year-olds and a 46-year-old man were questioned but later released.

GETTY Police said the Essen victims were attacked in three parts of the city by North African men

Police spokesman Peter Elke said: "The heavy police presence on the ground meant we could promptly identify and arrest some suspected attackers."

The sequence of events has to be determined Police spokesman

All suspects are immigrants or of a migrant background. Mr Elke added: "The sequence of events has to be determined. Therefore we are looking for witnesses to the attacks as enquiries continue." The festival continued on sunday and will end on Monday night.

Cologne: Sex Attacks and Robberies Tue, January 12, 2016 Thirty-one suspects, including 18 asylum seekers, are under investigation over offences including sexual assault and theft in Cologne on New Year's Eve. Far right protestors in Lepzig have rallied against refugees and German chancellor Angela Merkel. Play slideshow Reuters•Getty 1 of 22 Protestors in Lepzig rally after over 100 women were sexually assualted on New Year's Eve