The Turkish armed forces have begun a big naval exercise in the Mediterranean and Aegean Seas.

Turkey and Greece, which both belong to NATO, have territorial disputes in the Aegean and over the Mediterranean island of Cyprus, which have in the past brought them close to conflict.

But the BBC Ankara correspondent says tension in the area has cooled off over the last few months.

The Greek government has voiced concern over the new exercise, which will include an area close to the Greek island of Crete.

Both Turkey and Greece have taken part in separate naval exercises in the region in the past.