A top German police official says he doesn't believe New Year's Eve assaults in Cologne and elsewhere blamed largely on foreigners were linked to organized crime.

Authorities are looking into whether the robberies and sexual assaults by groups of men in Cologne were coordinated or linked to smaller-scale incidents in other cities.

Holger Muench, the head of Germany's Federal Criminal Police Office, told RBB Inforadio on Tuesday that "the same conditions were in place at different locations," with crowds of people gathering to celebrate the new year. He added: "I am not saying that there was no organization, but it is not organized crime — that would have a different quality for me, we would be talking about ... hierarchical groups."

The assaults have heightened tensions over Germany's migrant influx.