The likely cancellation of a visit to Athens by Turkish Foreign Minister Abdullah Gul and signs of increasing military tension over the Aegean Sea could be signaling the start of a rough patch in Greece’s ties with its eastern neighbor, diplomatic sources said yesterday.

Gul appears to have postponed his much anticipated visit to Athens this month but the reasons for the change in his travel plans are not clear.

Diplomatic sources also expressed their concern over Turkish fighter jets violating Greek air space.

The number of violations have remained steady but Turkish jets involved appear to be all carrying weapons and have been engaging in mock dogfights with Greek forces, sources said.

Senior defense ministry officials from both sides had said last year they will look into fighter planes flying over the Aegean unarmed as a way of avoiding possible tension.

Ties with Turkey took a hit earlier this month when NATO canceled its participation in a planned military exercise in the northeastern Aegean due to Turkish calls to demilitarize the island of Aghios Efstathios.

Athens saw the decision as breaching international law and its national sovereignty.

Despite broader concerns over escalating tension between the two countries, Greek Defense Ministry sources pointed out that there was no indication of increased activity on Turkey’s shores from its armed forces.