Two other officials from the National Intelligence Organisation (MIT) have also been called to testify, said Anatolia.

Fidan is known for secretly talking to the PKK in 2010, which was also confirmed by Prime Minister Recep Tayyip Erdogan.

Recordings of the talks, which took place in Oslo, were leaked in the media last year, sparking the ire of the opposition and sending shockwaves through a public opinion accustomed to Ankara's long-standing blanket refusal to talk to the PKK.

But the talks did not lead to a concrete solution of the problem as fighting between Turkey's military and Kurdish rebels has escalated.

In recent months, the government has also intensified pressure on alleged sympathisers of the Kurdish separatist rebels.

The drive is part of a crackdown on the banned Kurdish Communities Union (KCK), the suspected political wing of the PKK. Anatolia said Fidan and two other MIT officials would testify as part of an ongoing probe into the KCK.

The PKK took up arms in southeastern Turkey in 1984, sparking a conflict that has claimed about 45,000 lives. It is labelled a terrorist outfit by Ankara and much of the international community.