Victims have described chaos outside the city's main station, as the men carried out dozens of attacks with little apparent response from the authorities.

Correspondents say the identification of the attackers as North African or Arab in appearance has caused alarm in Germany because of the influx of more than a million migrants and refugees in the past year.

Some of the women caught in the violence have begun speaking of their ordeal.
'Surrounded by 20 to 30 men'
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Media caption"Twenty or 30 men surrounded us and we couldn't even move anymore"

Michelle told the BBC News how she and her friends became surrounded by between 20 and 30 men, who were speaking a foreign language.

"They grabbed our arms... pushed our clothes away, and tried to get between our legs or I don't know where.

"They got everything we had in our pockets."

She said German police needed to provide more protection for women and girls.

"We are all really shocked that something like this could happen, especially at an event like New Year's Eve."

The search for answers
'I thought they could kill us, and nobody would notice'
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Media caption"I thought if we stayed here, in this crowd, they could kill us ... and nobody would notice"

One woman, whose identity has been protected, told German television how gangs of men assaulted her in the crowd.

"All of a sudden these men around us began groping us," she said. "They touched our behinds and grabbed between our legs. They touched us everywhere.

"So my girlfriend wanted to get out of the crowd. When I turned around one guy grabbed my bag and ripped it off my body."

She said she felt in extreme danger, but there were no police officers to help.

"I thought to myself that if we stay here in this crowd they could kill us, they could rape us and nobody would notice. I thought we simply had to accept it.

"There was no one around us who helped or was in a position to help. All I wanted was to get out.

"I was scared that I wouldn't leave this crowd alive. I was scared that if someone showed up with a knife I could be raped in the middle of the street."