A Turkey-based Kurdish militant group has said it carried out Wednesday’s bomb attack in Ankara that killed 28 people.
The Kurdistan Freedom Hawks (TAK) group said on its website that the attack was in retaliation against the policies of President Recep Tayyip Erdogan.
Earlier, Mr Erdogan said he had “no doubt” that US-backed Syrian Kurdish groups carried out the bombing.
The TAK was once linked with the outlawed Kurdistan Workers Party (PKK).
Both it and the PKK are classified as terrorist groups by Turkey and the US.
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In a statement, the TAK said a 27-year-old Turkish national, Abdulbaki Sonmez, had carried out Wednesday’s rush-hour car-bombing on a Turkish military convoy in the country’s capital.
The group made reference to military operations against Kurdish rebels in south-east Turkey, and threatened more attacks.
Turkey had named the man who detonated the Ankara bomb as Salih Necar, a Syrian national and member of the People’s Protection Units (YPG).
The US supports the Syrian Kurdish Democratic Union Party (PYD) and its military wing, the YPG, in the fight against so-called Islamic State (IS).
Turkey strongly objects, citing their affiliation with the PKK, which it says played a supporting role in the Ankara bombing.
Continued American support for Syrian Kurds, reiterated by a state department spokesman this week, is threatening to cause a rift between the two Nato allies.
President Erdogan said he would tell President Barack Obama that US weapons had helped Syrian Kurds attack civilians.
Mr Erdogan pointed out that he had told President Obama months before that after three plane-loads of US weapons arrived, half ended up in the hands of fighters of so-called Islamic State and the rest with the PYD.
“They were used against civilians there and caused their deaths,” he complained.
The Turkish leader appeared to refer to a US air drop of military supplies in late 2014 meant for Iraqi Kurdish forces during the battle for the town of Kobane, Reuters reported.
As the Syrian army, backed by Russian air power, has targeted Syrian opposition forces and pushed further north in Aleppo province, the Syrian Kurdish militia has made gains from the rebels close to the Turkish border.
Turkey fears they could seize a 100km-stretch (62 miles) as far as Jarablus to create a large zone along the border.
The army has continued to shell YPG targets across the border near the rebel-held town of Azaz.
Turkey also has concerns that the PKK is being given support by the Syrian Kurdish militia in its battle with security forces in south-east Turkey.
“There’s close integration and there’s talk of tunnels for the flow of weapons,” Burhanettin Duran of the pro-government Seta research institute told the BBC.