The interception took place on Thursday, the Finnish Air Force said. The aircraft included a transport plane and several fighter jets. The Nordic air forces tracked the group and established its identity; officials did not report that the aircraft had entered either country’s airspace.

Swedish Prime Minister Ulf Kristersson said the operation demonstrated the countries’ cooperation under their Quick Reaction Alert arrangements and their ability to monitor and protect their airspace. The Swedish and Finnish air forces worked together during the response, which was publicly described as a first for the two countries.

The Gulf of Finland lies within a Baltic Sea region that has faced heightened security attention since Russia’s full-scale invasion of Ukraine in 2022. The source report cited earlier incidents involving pipeline outages, airspace violations and drone sightings as part of the backdrop to the alert posture.

Finland and Sweden joined NATO after decades of military non-alignment, following Russia’s invasion of Ukraine. Their Nordic neighbours Norway, Iceland and Denmark were already members, as were Estonia, Latvia and Lithuania. The joint interception underscored the closer defence coordination now taking shape among the Nordic allies, while the Russian embassies in Stockholm and Helsinki had not responded to requests for comment at the time of the report.