Helsinki police say a 20-something man was attacked with a gas spray at the Central Railway Station after 9 pm on Sunday evening.
Head of investigation Petri Juvonen says the victim is an asylum seeker. Juvonen says that a verbal exchange took place between the migrant protesters and Finnish onlookers, followed by one of the asylum seekers being sprayed in the eyes with an unidentified gas.
The incident was reported first by Helsingin Sanomat.
Specifically, says Juvonen, the victim and his friends were on their way to a public toilet near the Railway Station protest, but were impeded by a group of "Finnish men".
The incident has been reported to the police and the perpetrator is suspected of assault. The male attacker has not been apprehended at the time of writing, and police have not ascertained his motive.
The attack was first reported by Helsingin Sanomat.
Asylum seekers have protested against Finnish immigration policy at the Railway Station for several weeks, having constructed makeshift shelters by the nearby ice rink. Anti-immigration protesters have also set up their own smaller counter-demonstration nearby.