Greece's highest court has imposed severe restrictions on the movements of one of eight Turkish servicemen who have applied for asylum in Greece after fleeing Turkey following a failed 2016 coup there, while he waits for a decision on his asylum application.

The Council of State ruled that the officer will remain at an undisclosed address, must appear daily at a local police station and cannot obtain travel documents until his asylum application is determined in May.

Courts had initially granted him asylum, but suspended the decision following a Greek government appeal.

The eight helicopter crewmen, who deny involvement in the attempted putsch, have become a bone of contention in increasingly souring Greek-Turkish relations. Turkey demands they be returned as coup plotters, but Greek courts have rejected the extradition requests.