At least 28 people were killed and 81 injured in Ankara on Wednesday in an explosion which Turkey's prime minister on Thursday blamed on Syrian Kurdish groups.
The blast occurred during the Turkish capital's rush hour on Wednesday evening. Governor Mehmet Kilicer told state media officials believed the explosion came from a car bomb as a bus carrying military personnel passed by.
On Thursday, Turkey's Prime Minister Ahmet Davutoglu said the blast was carried out by a Syrian national with links to Syrian Kurdish militia, adding that authorities believe he collaborated with Turkey's Kurdish rebels to carry out the attack.
"The attack was carried out by the PKK (Kurdistan Workers' Party) together with a person who sneaked into Turkey from Syria," Davutoglu said, according to AP.
He added that nine people had been arrested since Wednesday evening's blast, and said that Turkey would retaliate against the Kurdish rebels in the wake of the attack.
In what appeared to be a veiled reference to fellow NATO members the U.S., Davutoglu urged Turkey's allies to cease supporting the Syrian Kurdish rebels, AP said.
The military wing of Syrian Democratic Union Party — the People's Protection Unit — is regarded as terrorist organization by Turkey due to its links to outlawed Kurdish groups. The People's Protection Unit have, however, been giving ground support to the U.S. in the fight against ISIS.
Later on Thursday, Turkish President Tayyip Erdogan said that evidence pointed to Syrian Kurdish militia involvement in Wednesday's attack, despite their denials.
He added that the attack will show the international community there are strong links between the outlawed PKK and the Syrian Kurdish groups, AP reported.
Also on Thursday, Turkey's military announced its jets had hit positions belonging to Kurdish rebels across the border in Iraq, with warplanes striking targets including a group of 60-70 people believed to be members of the PKK in the Haftanin region, AP reported.
Turkish jets have been hitting PKK positions in the north of Iraq ever since the collapse of a fragile peace process in July.
The Turkish Armed Forces also released a statement detailing another attack on a military convoy on the Diyarbakır-Lice highway in the south of the country on Thursday morning, in which six service personnel died.
On Wednesday, the Turkish military called the attack in Ankara "contemptible and dastardly," and said the blast explicitly targeted the military vehicles as they stopped at a traffic light.
Meanwhile, Omer Celik, ruling Justice and Development Party spokesman, described the blast as a "cowardly terror attack."
Hours after the blast, the U.S. State Department spokesperson released a statement strongly condemning the attack.
"We extend our deepest condolences to the families of those killed, and we wish a quick recovery to those injured," spokesperson for the State Department Mark Toner said. "We reaffirm our strong partnership with our NATO Ally Turkey in combatting the shared threat of terrorism."
The explosion follows a series of deadly attacks around Turkey over the past year, including a suicide bomber who killed 10 tourists in January.
The country's worst terror attack occurred in October of last year and killed 103 people. Turkish authorities have linked many of the attacks to ISIS.
Soon after the explosion, Turkey's government issued a temporary publication ban on local television and radio news stations reporting on the explosion.