By Samia Nakhoul and Nick Tattersall
ISTANBUL (Reuters) - Turkish Prime Minister Ahmet Davutoglu told Reuters on Wednesday some of the suspects in a suicide bombing that killed 97 people in Ankara had spent months in Syria and that they could be linked to Islamic State or to Kurdish militants.
"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 last Saturday's double suicide bombing in the heart of the capital, the worst attack of its kind on Turkish soil.
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.
(Additional reporting by Orhan Coskun and Asli Kandemir; editing by Ralph Boulton)