Turkish Prime Minister Ahmet Davutoglu told Reuters on Wednesday some of the suspects in suicide bombings that killed 97 people in Ankara had spent months in Syria and that they could be linked to Islamic State or to Kurdish militants.
The twin bombings targeting a rally of pro-Kurdish activists and civic groups in the heart of Ankara last Saturday drew anger from opponents of the government who condemn it for failing to prevent the worst attack of its kind on Turkish soil.
"We are working on (investigating) two terrorist organizations, Daesh (Islamic State) and PKK, because we have certain evidence regarding the suicide bombers having links with Daesh, but also some linkages with PKK groups," Davutoglu said in an interview in Istanbul.
"Some suspects were in Syria for many months."
Davutoglu said an investigation was underway into whether there had been intelligence and security failures in the run-up to the bombing, but said Turkey had foiled previous such attacks and that Ankara's police, intelligence and security chiefs had been removed from their posts.
He said Turkey had intelligence that militants from the Kurdistan Workers Party (PKK) and leftist Revolutionary People's Liberation Army-Front (DHKP-C), which claimed an attack on the U.S. consulate in Istanbul in August, had been trained as suicide bombers in northern Iraq and sent to Turkey.
Davutoglu also said Turkey had the right to defend itself against growing risks emanating from Syria after Russia's military intervention, which he said if anything showed the weakness of Syrian President Bashar al-Assad.
Syria's army along with Iranian and Hezbollah allies will soon launch a ground attack supported by Russian air strikes against insurgents in the Aleppo area, which is close to the Turkish border, two senior regional officials told Reuters on Tuesday.
"As a neighboring country we have serious concerns and we have certain rights ... based on international law to protect our homeland security," Davutoglu said.
"Now there are more risks in Syria than before after these new interventions. But at the end of the day the Syrian people should decide on their own future."
Asked whether Turkey would supply moderate Syrian rebels with weapons to face the Russian-led assault, he said the issue was one for the international community and not Turkey alone.
"This is not our problem only, this is the problem of the international community. It is a shame for the international community not to stop the war crimes of the Syrian regime and not to stop this barbaric Daesh group."