Four out of a total 14 Ankara blast suspects were released on Thursday, said police sources.

The four released suspects are believed to be linked to the sale of the car used in Sunday's suicide attack, and were among those detained in the southeastern province of Şanlıurfa.

The remaining 10 suspects are now in the anti-terror branch of the Ankara Police Department.

The car bomb attack in Ankara's central Kızılay neighborhood Sunday evening hit a major public transportation hub, killing 35 people and injuring dozens of others.

The TAK, a PKK-affiliated terrorist group, claimed responsibility for the blast on Thursday.

The Interior Ministry has identified the bomber as Seher Çağla Demir, 24, who joined the PKK terrorist group in 2013 and received training with the YPG in Syria.

The terrorist organization also admitted that the attack was committed by Demir, code-named "Doga Jiyan".