A Syrian national with links to Syrian Kurdish militia carried out the suicide bombing in Ankara that targeted military personnel and killed at least 28 people and wounded dozens of others, Turkey's prime minister says, and he has vowed retaliation.
Ahmet Davutoglu told reporters during a visit to Turkey's chief of military staff the Syrian man he identified as Sahih Neccar had carried out the attack in co-operation with Turkey's own outlawed Kurdish rebel group.
Authorities had detained nine people in connection with the attacks and were 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, striking at a group of about 60-70 rebels of the Kurdistan Workers' Party, or PKK.
There was no immediate claim of responsibility for the attack, which killed military personnel and civilians, although suspicion had immediately fallen on the PKK or the Islamic State group.
The leader of the main Syrian Kurdish group, Salih Muslim, denied his group was behind the Ankara attack and warned Turkey against taking Syria ground action.
The car bomb went off late on Wednesday (local time) 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.
The blast was the second deadly bombing in Ankara in four months.
Davutoglu said Syria's government, which he accused of backing Syrian Kurdish militias, is also to blame. And in an apparent reference to the US, he called on Turkey's allies to stop its support for the Syrian Kurdish group.
On Thursday, six soldiers were killed in southeastern Turkey after PKK rebels detonated a bomb as their military vehicle was passing by, the state-run Anadolu Agency reported.
The military said Thursday that Turkish jets attacked PKK positions in northern Iraq's Haftanin region, hitting the group of rebels which it said included a number of senior PKK leaders. The claim could not be verified.
Earlier, Yeni Safak, a newspaper close to the government, said the bomber had registered as a refugee in Turkey and Turkish authorities were able to identify him from his fingerprints.
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.
The attack came at a tense time when the Turkish government is facing an array of challenges. Hundreds of people have been killed in renewed fighting following the collapse of the peace process and tens of thousands have been displaced.
Turkey has also been helping efforts led by the US to combat the Islamic State group in neighbouring Syria, and has faced several deadly bombings in the past year that were blamed on IS.
The Syrian war is raging along Turkey's southern border. Recent air strikes by Russian and Syrian forces have prompted tens of thousands of Syrian refugees to flee to Turkey's border.