According to the Finnish Defence Forces, the accident was related to the use of a firearm.
The police are investigating into the incident. The Defence Forces will give more details of the incident later.
The accident was first reported by the Finnish language tabloid Ilta-Sanomat.
The Defence Forces does not suspect foul play in the incident.
The family members of the deceased have been informed, and a crisis support group has been set up.
The Western Uusimaa Police Department will investigate into the matter.
