Finnish lawmakers agreed on Tuesday to urgently introduce tougher measures against foreign-born criminals, after recent outrage at a string of migrant men arrested over alleged sexual abuse of girls.
The measures could include raising the minimum sentence for child sexual abuse, or revoking Finnish citizenship from convicted sexual offenders with a foreign background.
Police in the capital Helsinki said on Saturday they had detained three men of foreign background on suspicion of multiple counts of aggravated child sexual assault and child rape.
Two of the men were later released, while police indicated they expect to formally charge the third man this week.
In recent weeks a series of similar arrests have been made in Oulu, a Finnish town some 200 kilometres (124 miles) south of the Arctic Circle.
Oulu police said on Friday they had arrested three new suspects in relation to four investigations of alleged rape and sexual abuse of girls under 15.
In December police in the town arrested at least nine suspects, all of whom had arrived in Finland as refugees or asylum seekers, for suspected sexual offences against children.
Police also warned girls and their parents to beware of sexual offenders looking to lure victims on social media.