Turkey's Ground Forces Chief General Isik Kosaner attends a ceremony in Ankara, in this July 16, 2010 file picture. [Photo/Agencies]

ANKARA - Turkey's top army leaders, namely chief of general staff Isik Kosaner, top commanders of the land forces, air forces and navy resigned on Friday, according to the NTV, a private news channel in Turkey.

Commanders-in-chief of the army forces said they have handed in their resignation to Turkish Prime Minister Recep Tayyip Erdogan, the NTV said. One of the channel's commentator described the event as an unprecedented crisis in the history of the Turkish army.

Isik Kosaner said his resignation is upon a necessity, while the other three commanders did not explain.