Finland is requesting an explanation for the incident, according to the ministry's statement on social media.
On Thursday afternoon, a Russian reconnaissance aircraft is suspected of flying into Finnish airspace over the central Baltic Sea, southeast of Åland, in the area where the Archipelago Sea and the Gulf of Finland meet.
Defense Minister Antti Häkkänen said initially that the matter was being taken seriously and would be investigated further.
The Finnish Border Guard announced on Friday that the violation lasted three minutes and extended 4.7 nautical miles into Finnish territory, Yle reports.
