Poland's four F-16 are stationed in an air base in Siauliai, northern Lithuania.

Captain Tomas Pakalniskis, spokesman for the army's Joint Staff, said two of them took off earlier this week to identify and intercept a Russian reconnaissance aircraft Il-20 above the Baltic Sea.

"On May 15, we spotted an object flying from continental Russia to the Kaliningrad region. We scrambled two F-16 jets and identified the Il-20," the officer told BNS on Thursday.

"This was the first scramble of the Polish troops who joined the NATO air-policing mission earlier in May," he added.

Pakalniskis said the Russian warplane had its automatic onboard transponder off while flying in the international airspace.

This is the seventh time Polish aviators are serving in the NATO air-policing mission in the Baltic states, with four fighter-jets stationed in Estonia by Spain to support them.

NATO launched its air-policing mission in the Baltic states immediately after Lithuania, Latvia and Estonia joined the Alliance in 2004. Three years ago, the mission was backed up with additional fighter-jets in response to the annexation of Crimea by Russia.