Separately, Germany said it had closed its embassy in Ankara due to indications that an attack could be imminent. The consulate and German school in Istanbul were also closed, it said, according to Reuters.

Read alsoErdogan: Attacks like Ankara blast will not weaken Turkey's resolveTAK had previously claimed responsibility for car bombing in Ankara last month that killed 29 people. Ankara has now been hit by three bombings in a space of five months, ratcheting up security fears across the city and Turkey.