A SYRIAN national with links to Syrian Kurdish militia carried out the suicide bombing in Ankara that killed at least 28 people and injured dozens of others, Turkey's prime minister has said.
Ahmet Davutoglu said Sahih Neccar carried out the attack in cooperation with Turkey's own outlawed Kurdish rebel group.
Authorities have detained 14 people in connection with the attacks and are trying to identify others.
Turkey's military, meanwhile, said its jets conducted cross-border raids against Kurdish rebel positions in northern Iraq hours after the Ankara attack.
"It has been determined with certainty that this attack was carried out by members of the separatist terror organisation together with a member of the YPG who infiltrated from Syria," Mr Davutoglu said, referring to the Kurdistan Workers' Party as well as Syrian Kurdish militia group the People's Protection Units.
There was no immediate admission of responsibility for the attack, which killed military personnel and civilians, although suspicion had immediately fallen on the PKK or Islamic State.
Salih Muslim, leader of the main Syrian Kurdish group, that denied his group was behind the bombing and warned Turkey against taking ground action in Syria.
President Recep Tayyip Erdogan said that despite the denials, evidence obtained by the Turkish authorities pointed to the group.
"Despite the fact that their leader says they have nothing to do with this, the information and documents obtained by our interior ministry and all our intelligence organisations shows that (the attack) was theirs," he said.
The car bomb went off late on Wednesday in Turkey's capital during evening rush hour.
It exploded near buses carrying military personnel that had stopped at traffic lights in an area close to parliament and armed forces headquarters and lodgings.
Mr Davutoglu said Syria's government, which he accused of backing Syrian Kurdish militias, is also to blame.
In an apparent reference to the US, he called on Turkey's allies to stop its support for the Syrian Kurdish group.
Mr Erdogan said the attack would show the international community the strong links that exist between the PKK and the Syrian Kurdish militias.
Yesterday six soldiers were killed in south-east Turkey after PKK rebels detonated a bomb on a road linking the cities of Diyarbakir and Bingol as their military vehicle was passing by, the state-run Anadolu Agency reported.
The military said on Thursday that Turkish jets attacked PKK positions in northern Iraq's Haftanin region, hitting a group of 60 to 70 rebels which it said included a number of senior PKK leaders. The claim could not be verified.
Turkey's air force has been striking PKK positions in northern Iraq since a fragile two-and-a-half-year-old peace process with the group collapsed in July, reigniting a fierce three-decade old conflict.
In October, suicide bombings blamed on IS targeted a peace rally outside the main train station in Ankara, killing 102 people in Turkey's deadliest attack in years.
