Turkey has issued arrest warrants for 48 Kurdish fighters, including the leader of a US-backed Syrian Kurdish group that is a key military force against ISIL.
Warrants were issued on Tuesday in connection with a suicide bomb attack in February in Ankara. The attack on a military bus near a main base killed 29 people and was claimed by a group linked to the outlawed Kurdistan Workers' Party, or PKK.
Turkey's state-run Anadolu news agency said those wanted include two alleged PKK leaders currently in exile in Europe, including Salih Muslim, leader of the Syrian Kurdish Democratic Union Party, or PYD.
Muslim has repeatedly denied any "operational links" to the PKK.
He told Al Jazeera that his group had nothing to do with the February attack, or any others inside Turkey.
"It's not true. We don't have any relation with any organisation outside of Syria. It's an internal matter for Turkey. It wasn't related to Syria at all," Muslim said on the phone from London.
His PYD's armed wing is the YPG, or People's Protection Units, which is the primary ground partner for the US-led coalition in its battle against ISIL in northern Syria.
Al Jazeera's Osama bin Javaid, reporting from Gaziantep on the Turkey-Syrian border, noted that Ankara has launched Operation Euphrates Shield - with troops inside northern Syira - in an effort to sweep Kurdish forces out of the region.
"If you ask Turkey's ally the United States, it differentiates between the two organisations - PKK and PYD. The PKK operates in Turkey and the PYD operates in Syria. The United States - even US troops - is closely linked to anti-ISIL operations being carried out in northern Syria with the YPG."
Javaid noted when the arrests announced on Tuesday play out, it could have repercussions between Ankara and Washington.
Ankara says the Kurdish PYD and YPG are an extension of the PKK in Syria. All three are designated as "terrorist" organisations.
The Turkish military launched Operation Euphrates Shield on August 24, entering Syria with the aim of both clearing ISIL from the border region and preventing the expansion of a Kurdish-controlled autonomous region.
The Turkish military and its allied rebel forces have so far seized control of about 1,620 square kilometres of territory, according to the military.
On Tuesday, Turkish President Recep Tayyip Erdogan renewed a threat to oust Syrian Kurds from a key town in northern Syria.
Erdogan reiterated that Turkish-backed fighters were close to capturing al-Bab from ISIL. Once that is achieved, Erdogan said, the troops would head towards the town of Manbij, currently held by the US-backed Kurdish forces.
Kurdish forces drove ISIL from Manbij earlier this year, but Turkey said it was promised they would leave after the town's capture and retreat east of the Euphrates river.
"Why will we go to Manbij? Not because we are wild about the place but because the PYD and YPG are there," Erdogan said. "They say a number of them have left. But we want the place to be totally emptied of the PYD and YPG."