Prime Minister Ahmet Davutoglu says Turkey is investigating the Islamic State group as the prime suspect in the bombings on a weekend peace rally in Ankara that killed 97 people.
"Looking at how the incident took place, we are probing Daesh as our first priority," Davutoglu said, using an alternative Arabic name for IS.
He said that the attacks were definitely carried out by two suicide bombers.
"We are close to identifying one of the bombers," he told NTV television, adding that this would help name the organisation behind the attacks.
Davutoglu however remained cautious, saying that authorities were investigating three groups including Islamic State but also the outlawed Kurdistan Workers' Party and the far-left Revolutionary People's Liberation Party-Front as "potential suspects."
"It would not be accurate to give an indication right now," he said.
At least 97 people were killed in the double suicide bombing against the peace rally by leftist and pro-Kurdish activists in central Ankara, the deadliest attack in the history of modern Turkey.