Turkish President Recep Tayyip Erdogan says Turkey has received intelligence reports suggesting that a double suicide bombing in Ankara that killed 97 people on October 10 was planned by militants who "originated" the attacks from Syria.
Erdogan said authorities are not ruling out any groups in their investigation into the deadly attack on a peace rally.
He said the search for culprits includes investigations into possible links with Islamic State (IS) militants and the outlawed Kurdistan Workers Party (PKK).
But Erdogan rejected suggestions from a pro-Kurdish party that state officials may have had a hand in the attacks against left-wing opposition supporters and Kurdish activists, saying the accusations were based on gossip.
Erdogan says he has ordered Turkey's State Supervisory Council (DDK) to conduct a special probes into the Ankara bombings, which also injured hundreds of people.
The DDK is an inspection body attached to the Turkish presidency.
Its probe is to be held in parallel with a regular police and judicial investigation.