Finland's Defence Ministry said on Wednesday it suspected a Russian military aircraft of violating Finnish airspace, prompting an immediate investigation and a response by the Finnish Air Force.
Defence Minister Antti Häkkänen said the aircraft may have been evading a thunderstorm in the Gulf of Finland off the Porkkala Peninsula, between Finland and Estonia.
"An investigation into the alleged airspace violation was launched immediately," he said in a statement.
The Finnish Air Force scrambled aircraft in response, while the Border Guard was tasked with investigating the incident further.
Stray Ukrainian drones have repeatedly entered Finnish airspace or crashed on Finnish soil in recent months. Finland shares a border with Russia stretching over 1,300 kilometres.