Greek and Turkish fighter jets collided in disputed airspace over the Aegean Sea Tuesday, injuring the Turkish pilot and leaving the Greek pilot missing.
Both sides are giving conflicting accounts of the incident.
Turkey says Greek warplanes tried to intercept the Turkish jets during maneuvers in what Turkey calls international airspace.
Greece says three Turkish jets flew into its airspace and headed towards the island of Crete without informing anyone of their flight plans.
Turkey said the Greek pilot was killed, but Greece says the pilot is missing and is searching the Aegean for him.
The Greek and Turkish foreign ministers, Dora Bakoyannis and Abdullah Gul spoke after the incident and said it should not affect relations.
Turkey and Greece came close to a war about 10 years ago. Ties between Athens and Ankara have improved considerably since that crisis, but the two sides have not made progress in efforts to resolve their territorial disputes in the Aegean Sea.
U.S. State Department spokesman Sean McCormack said the United States urges Greece and Turkey - two NATO allies - to work together to avoid such accidents.
Some information for this report was provided by AFP and Reuters.