There is a very small Turkish exclave in Syria called the Tomb of Suleiman Shah which is in Lake Assad about 30 km (18 miles) south of the Turkish-Syrian border.
The exclave was created by article 9 of the Franco-Turkish Ankara Agreement of 1921 and is currently guarded by 25 Turkish soldiers.
This week ISIS, an al-Qaeda affiliated group in Syria, took control of the area around the exclave after battles in which it defeated and expelled other rebel groups from the area.
al-Qaeda, and ISIS, have a history of destroying tombs and the Turkish Government has issued warnings stating that no rebel groups should attempt to capture or enter the exclave, while at the same time the Turkish Air Force and Army have been put on alert to respond if the ISIS makes any hostile moves towards the exclave.
Google Maps link for the Tomb of Suleiman Shah:
Article 9 of the Franco-Turkish Ankara Agreement of 1921
The tomb of Suleiman Shah, the grandfather of the Sultan Osman, founder of the Ottoman dynasty (the tomb known under the name of Turk Mezari), situated at Jaber-Kalesi shall remain, with its appurtenances, the property of Turkey, who may appoint guardians for it and may hoist the Turkish flag there.
Update: In a strange turn of events it is now being reported that Kurdish groups have begun to assist rebel groups in the area and together they are trying to defeat and expel the ISIS from the area near the tomb.