Police shot and injured a person who was posing a threat to officers on Thursday at around noon in the centre of Kirkkonummi, according to the Western Uusimaa Police Department.
Police said the incident is being investigated as a case of attempted murder of police.
The injured suspect received first aid at the scene immediately from officers and members of emergency services and was transported to the hospital for follow-up treatment, police said.
"Police used a gun to stop a dangerous person. We do not know any more about the incident at this stage," the National Bureau of Investigation's (NBI) Detective Chief Inspector, Jan Aarnisalo, told Yle.
Police have cordoned off the scene in order to carry out a technical investigation.
Authorities did not reveal the precise location of the incident, but said that it is safe for people to move around Kirkkonummi.
Along with a yet-to-be announced preliminary investigation by police, the prosecutor will also investigate the police's use of a firearm.