MOSCOW, June 27 (Reuters) - Russia's defence ministry said early on Tuesday that it was conducting tactical fighter jet exercises over the Baltic Sea with the main goal of testing readiness to perform combat and special tasks operations.

"The crews of the Su-27 (fighter jets) of the Baltic Fleet fired from airborne weapons at cruise missiles and mock enemy aircraft," the ministry said on the Telegram messaging app.

"The main goal of the exercise is to test the readiness of the flight crew to perform combat and special tasks as intended."

The ministry said that in addition to improving skills, the fighter jets crews are on "round-the-clock combat duty" guarding the air space of Russia's Kaliningrad exclave.