Istanbul: Turkish President Tayyip Erdogan said US-supplied weapons had been used against civilians by a Syrian Kurdish militia group that Ankara blames for a deadly suicide bombing, and said he would talk to US President Barack Obama about it later on Friday.

US support for the Syrian Kurdish Democratic Union Party (PYD), which Washington considers a useful ally in the fight against Daesh, has enraged Turkey and risks driving a wedge between the Nato allies. Turkey sees the group as a terrorist organisation linked to Kurdish militants waging an insurgency on its own soil.

Erdogan and the Turkish government have said the PYD’s armed wing, the YPG, was responsible for a suicide car bomb attack in the administrative heart of the capital, Ankara, on Wednesday, which killed 28 people, most of them soldiers.

Erdogan said he was saddened by the West’s refusal to call the PYD and YPG a terrorist group, and would explain to Obama by phone how weapons provided by the US had aided them.

“I will tell him, look at how and where those weapons you provided were fired,” he told reporters in Istanbul.

“Months ago in my meeting with him [Obama], I told him the US was supplying weapons. Three plane loads arrived, half of them ended up in the hands of Daesh, and half of them in the hands of the PYD,” he said.

“Against whom were these weapons used? They were used against civilians there and caused their deaths.” He appeared to be referring to a US air drop of 28 bundles of military supplies in late 2014 meant for Iraqi Kurdish fighters near the Syrian city of Kobani. Pentagon officials said at the time one had fallen into the hands of Daesh. The Pentagon later said it had targeted the missing bundle in an air strike and destroyed it.

Turkish Foreign Minister Mevlut Cavusoglu earlier accused the US of making conflicting statements about the Syrian Kurdish militia.

He said US Secretary of State John Kerry had told him the Kurdish insurgents could not be trusted, in what Cavusoglu said was a departure from Washington’s official position.

The United States has said it does not consider the YPG a terrorist group. A spokesman for the State Department said on Thursday Washington was not in a position to confirm or deny Turkey’s charge that the YPG was behind the Ankara bombing.

The spokesman also called on Turkey to stop its recent shelling of the YPG. The YPG’s political arm has denied the group was behind the Ankara attack and said Turkey was using it to justify an escalation in fighting in northern Syria.