The women entered the main central Stockholm mosque at around 11am on Saturday.
Mosque employees called the police who dispatched several units to the scene. Shortly after their arrival they emerged with the still bare-breasted women and walked to a transport vehicle.
According to the duty police officer Jonas Svalan the women are now suspected of disorderly conduct due to their nudity and assault for having allegedly shoved somebody.
The women are reported to originate from Egypt, Tunisia and Sweden.
Femen is originally a Ukrainian women's group that applies "sextremism" to draw attention to equality and democracy issues.
The group's perhaps most high profile campaign came during the European Football Championship in 2012 when Femen's bare-breasted leaders capitalized on the massive media presence to stage protests against sex trafficking.
The group has recently been very active in France and only last week several activists accosted the French President François Hollande as he visited the Paris airshow.
Earlier this year they caused outrage when they bared all at Notre Dame Cathedral in Paris to bid their own 'adieu' to Pope Benedict.