Finnish and Swedish fighter jets on Monday carried out a joint mission over the Baltic Sea, the Nato military alliance reported on Wednesday.
Nato's Combined Air Operation Centre in Uedem, Germany, detected two Russian fighter jets over international waters in the Baltic Sea.
The jets had taken off from Kaliningrad and were heading towards mainland Russia.
The Russian jets had no flight plan, were not in radio contact with civilian air traffic control, and did not use transponder signals, as is customary under international aviation rules, according to the Nato release.
The aircraft were also tracked by Finnish and Swedish air operation centres. Both allies launched their quick reaction alert (QRA) forces to intercept the Russian military aircraft in coordination with the Nato aviation base in Germany.
Ilta-Sanomat was the first to report the news.
