Finland and Sweden carried out their first joint operational identification mission on Sept. 24, scrambling fighter jets to intercept Russian military aircraft over the Gulf of Finland, the Swedish Armed Forces said.

Finnish F/A-18 Hornets and Swedish JAS 39 Gripens identified a formation containing a Tu-134 transport aircraft, MiG-31 interceptors and Su-30 fighters. Finland’s Air Operations Centre led the mission. The Russian aircraft were in international airspace, and the announcement did not report an airspace violation.

The operation followed an expansion of cooperation this autumn that allows the two countries to conduct joint identification missions and use each other’s air bases, according to Col. Vesa Mäntylä, deputy chief of staff at Finland’s Air Force Command.

Fighters assigned to Quick Reaction Alert remain mainly at bases in their own countries but can operate from across the border when needed.

The mission followed years of frequent cross-border training. Both air forces also work with Denmark and Norway through Nordic Air Power cooperation and coordinate with NATO’s Baltic air-policing forces.

Finland and Sweden joined NATO after Russia’s full-scale invasion of Ukraine, ending their longstanding military nonalignment. Swedish Prime Minister Ulf Kristersson described the joint intercept as a practical demonstration of the readiness and trust built between the two countries, Reuters reported.