German police have identified three suspects in connection with attacks on women at New Year's celebrations in the city of Cologne but have not yet made any arrests, the interior minister of the state of North Rhine-Westphalia (NRW) said on Wednesday.

About 90 women reported being robbed, threatened or sexually molested at New Year's celebrations outside the city's cathedral by young, mostly drunk, men, police said on Tuesday, in events they described as "a new dimension in crime."

The police chief in Cologne has said the perpetrators appeared to be of "Arab or North African" origin, prompting right-wing groups to condemn the government for its welcoming stance toward refugees fleeing war in Syria and elsewhere.