Berlin - Germany's Justice Minister Heiko Maas said Sunday that the shocking spate of sexual assaults during New Year festivities in Cologne was organised.
"For such a horde of people to meet and commit such crimes, it has to have been planned somehow," he told Bild am Sonntag newspaper.
"No one can tell me that this was not coordinated or planned. The suspicion is that a specific date and an expected crowd was picked," he said, adding that if confirmed, that would "take on a new dimension".
Quoting confidential police reports, Bild am Sonntag said some North Africans had sent out calls using social networks for people to gather in Cologne on New Year's Eve.
Young men not only from Cologne, but as far as France and Belgium responded to the call to travel to the western German city, the newspaper said.
Cologne police said they have now recorded 379 cases of New Year's Eve violence - ranging from groping to theft to two reported rapes - with asylum seekers and illegal migrants from North Africa making up the majority of suspects.
The allegations have stoked criticism of Merkel's liberal open-door policy - which brought 1.1 million new asylum seekers to Germany last year.