Swedish police say at least 15 young women have reported being groped by groups of men on New Year's Eve in the city of Kalmar.

The Swedish reports follow a string of sex assaults and robberies during New Year's celebrations in Germany.

Kalmar police spokesman Johan Bruun on Friday said groups of men encircled women on a crowded square and groped them. He said no one was physically injured but that many of those targeted were terrified.

He said two men, both asylum-seekers, were informed through interpreters that they're suspected of sexual assault and that police are trying to identify other suspects.

Asked about similarities to assaults in Germany, Bruun said "we are aware of what happened in Germany but we are focusing our investigation on what happened in Kalmar."

German authorities say they have identified 18 asylum-seekers among 32 suspects linked to crimes committed in Cologne at New Year.

A spokesman for the Interior Ministry says the suspects were detained by federal police.

Tobias Plate told reporters in Berlin on Friday that those detained are suspected of crimes ranging from theft to assault.

None is currently suspected of committing sexual assaults of the kind that have prompted outrage in Germany over the past week.