A 21-year-old man and three minors have been arrested on suspicion of raping two teenaged girls in the western German town of Weil am Rhein.

The victims and the 21-year-old accused were acquainted. The girls met up with him on New Year's Eve and followed him to his flat, where they initially engaged in consensual sexual activity, police said.

The situation escalated, resulting in the man, his 15-year-old brother and two other 14-year-old boys repeatedly raping the girls, police said.

All four suspects are Syrians, according to police, though it is unclear whether they are refugees currently seeking asylum or have been in the country longer.

There is no apparent connection to the mass sexual assaults committed in Cologne on New Year's Eve.