Turkish prosecutors are investigating whether Prime Minister Recep Tayyip Erdogan once referred to jailed Kurdish rebel leader Abdullah Ocalan as esteemed.
Turkey's main opposition party says Mr. Erdogan referred to Ocalan as "Sayin" or esteemed during a 2000 interview. Prosecutors are examining recordings of the comments.
Praising Ocalan is a criminal offense in Turkey. Several Kurdish politicians are facing charges of referring to him in the honorific.
Mr. Erdogan's allies say he never referred to Ocalan in the honorific.
Mr. Erdogan, as a member of parliament, has immunity from criminal prosecution. He is considering running for Turkish president in May elections.
Ocalan heads the Kurdistan Workers Party, PKK, which has been fighting for autonomy in southeastern Turkey since 1984. He was captured and convicted in 1999.
Some information for this report was provided by AP and Reuters.