On June 10, a Russian warplane violated Finnish airspace for the first time since Finland joined NATO last year.
The plane entered Finland's airspace for approximately two minutes on Monday morning, according to a statement from the country's defense ministry. The incident took place in the eastern Gulf of Finland, with the aircraft flying 2.5 kilometers into Finnish territory.
"We take the suspected territorial violation seriously and the investigation has been started immediately," Finnish Defense Minister Antti Hakkanen said.
The last similar incident occurred in August 2022, when two Russian fighter jets entered Finland’s airspace.
Finland, which guards a 1,300-kilometer border with Russia, is now part of NATO's eastern flank.
Russian President Vladimir Putin said in December 2023 that Finland is "now going to have problems" because it joined NATO.
In an interview with state-run television, Putin promised that Russia would create a "Leningrad military district" on the border with Finland and concentrate forces there.
Recently, NATO fighter jets have increasingly intercepted Russian aircraft near the alliance's airspace over the Baltic Sea.