Two Russian MiG-31 fighter jets are suspected of violating Finnish airspace near the coastal city of Porvoo on the Gulf of Finland.
The suspected violation happened at 06:40 GMT on Thursday and the jets were westbound, the defence ministry’s communications chief Kristian Vakkuri said, adding the aircraft were in Finnish airspace for two minutes.
“The depth of the suspected violation into Finnish airspace was one kilometre,” Vakkuri said but he would not elaborate on whether the planes were escorted out.
The Finnish air force sent up “an operational flight mission” and identified the MiG-31 jets and the Border Guard launched an investigation into the violation.
The incident came as Finland seeks NATO membership following Russia’s invasion of Ukraine.
Finland, which shares a 1,300-km (800-mile) eastern border with Russia, reversed decades of military non-alignment by seeking membership in the North Atlantic alliance in May, after being rattled by Moscow’s attack on Ukraine.
The Finnish Security and Intelligence Service warned in May that “Russia has the will” to influence Finland’s NATO application process, and “various attempts to do so are to be expected”.
All 30 members of the North Atlantic Treaty Organization must agree if Finland and Sweden, officially non-aligned but longtime adjunct partners of the alliance, are admitted. Ratification could take up to a year.
Finland and Sweden’s accession to NATO would mark one of the biggest shifts in European security in decades and further increase Russia’s strategic isolation.
According to a NATO list, seven member countries have yet to formally agree to the new double-entry: the Czech Republic, Greece, Hungary, Portugal, Slovakia, Spain and Turkey.
Turkey has raised a challenge demanding certain concessions from Finland and Sweden to back their memberships. Ankara has demanded the extradition of dozens of government opponents it has labelled “terrorists” from both countries in exchange for its support.