Finnish authorities suspect a Russian military plane entered Finnish airspace without permission on Monday morning.
The suspected violation occurred in the Gulf of Finland near the coastal town of Loviisa in the southeast of the country.
According to Yle's information, the aircraft flew in Finnish airspace for about two minutes, and was at one point 2.5 kilometres inside Finnish territory.
"We take this suspected territorial violation seriously, and an investigation has been immediately launched," Defence Minister Antti Häkkänen (NCP) said, adding that the Finnish Border Guard is responsible for investigating the matter.
The previous confirmed violation of Finnish airspace by Russia occurred in August 2022, when two Russian MiG-31 fighter jets flew into Finnish airspace near the city of Porvoo for about two minutes.