A Kurdish militant group on Friday claimed responsibility for a suicide car bomb attack in the Turkish capital Ankara which killed 28 people.
In a statement posted on its website, the Kurdistan Freedom Falcons said it carried out the attack to avenge Turkish military operations against Kurdish rebels in southeast Turkey. The Turkey-based group is considered an offshoot of the Kurdistan Workers' Party, or PKK, and has carried out several violent attacks in the past.
Turkey had blamed a U.S.-backed Syrian Kurdish militia group for the attack, saying they had acted in collaboration with the PKK.
Prime Minister Ahmet Davutoglu had identified the bomber as Syrian national Salih Neccar and said he was a member of the Syrian Kurdish militia group People's Protection Units, or YPG.
Following the attack, Turkey stepped up pressure on the United States and other allies to cut off support to the militia group. Turkey views the YPG as a terror group because of its affiliation with the PKK.
The YPG, however, has been most effective in the fight against the Islamic State group in Syria.
The Kurdistan Freedom Falcons, also known as TAK, however, named the bomber as Abdulbaki Sonmez.
"This act was conducted to avenge the massacre of defenceless, injured civilians," the group said, in reference to a large-scale Turkish security operation against militants in the town of Cizre. Rights groups have raised serious concerns over the operation in the town, which has been placed under a curfew that prevents journalists and observers from entering.
The group threatened further attacks in Turkey. Most recently, TAK had claimed responsibility for a mortar attack in December at Istanbul's second airport that killed a cleaner. It said the attack was in retaliation to the military's stepped up operations against the PKK.
On Friday, Turkish authorities said they had detained three more suspects in connection with the bombing in Ankara, raising the number of people in custody to 17, the state-run Anadolu Agency said. The latest suspects are believed to be linked to the PKK, it said.
Turkey's military pushed ahead with its cross-border artillery shelling campaign against YPG positions in Syria, Anadolu reported.
President Recep Tayyip Erdogan said three of the detained suspects are believed to have played "an active part" in the attack.
Erdogan said Friday that Turkish authorities don't have the slightest doubt that the YPG and its political arm, the Democratic Union Party, or PYD, were behind the bombing and said Turkey was saddened by its Western allies' failure to brand them as terrorist groups.
Speaking to reporters following Friday prayers in Istanbul, Erdogan also said he would take up the issue with U.S. President Barack Obama later in the day.
The White House later confirmed that Obama and Erdogan discussed Syria over the telephone Friday. Obama also offered his condolences for deadly terrorist attack in Turkey this week, it said.
Anadolu reported late Thursday that Turkish artillery units were "intermittently" firing shells into Syria, targeting militia positions near the village of Ayn Daqna, south of the town of Azaz.
The leader of the main Syrian Kurdish group, Salih Muslim, has denied his group was behind the bombing, and he warned Turkey against taking ground action in Syria.
Ankara appears increasingly uneasy over the group's recent gains across its border and has continued to shell the militia despite international calls for it to stop.
Davutoglu, accompanied by other ministers, placed 28 carnations at the site of the attack Friday in honour of the dead. Hundreds of people, meanwhile, filled two main mosques in Ankara for the funerals of at least eight of the victims.
The attack was the second bombing in the capital in four months.