NATO has begun its largest air deployment exercise since its establishment in 1949 in an apparent show of its deterrence capabilities.

The military exercise began at a base in northern Germany and elsewhere on Monday, with 250 fighter and other aircraft and 10,000 personnel from 25 NATO and other countries participating.

Senior officers of Japan's Air Self-Defense Force are scheduled to take part as observers, making them the only participants from Asia.

During the exercise, which runs through June 23, participating nations aim to boost coordination among their air forces by playing out a scenario of attacks on a NATO member mainly over German skies.

Drills include those for countering drone and ballistic missile attacks, which Russia has been using to inflict heavy damage on Ukraine during its invasion of the country.

The German military, the host of the drills, says the exercise had been planned before the Russian aggression.

But it says air capabilities have become even more important after the invasion and it is necessary to show NATO's deterrence.