Istanbul (AFP) - Turkey and the US were on a collision course Tuesday as President Recep Tayyip Erdogan threatened to "eliminate" a Kurdish militia in northern Syria -- a move deemed "unacceptable" by the Pentagon.
Erdogan has repeatedly warned that it is preparing an offensive into Syria against the Kurdish YPG militia, which the US has supported as the main fighting force against the Islamic State group.
"Turkey has the right to eliminate all threats against its national security," he said in a televised speech in Ankara.
"God willing, we will carry the process started with (previous offensives into Syria) to the next stage very soon."
US defence officials have been locked in talks with their counterparts in the Turkish capital since early Monday, trying to hash out a buffer zone deal that would persuade Turkey to hold off on a military attack.
"Clearly we believe any unilateral action by them would be unacceptable," US Defense Secretary Mark Esper told reporters in Tokyo on a trip through Asia.
"And so what we are trying to do now is work out with them an arrangement to address their concerns and I am hopeful we will get there... what we are trying to do is prevent unilateral incursions," he said.
But so far, Turkey has been unimpressed with US "safe zone" proposals which it says do not keep the YPG far enough away from the Turkish border.
It sees the YPG as an offshoot of the Kurdish PKK, which has fought a bloody separatist insurgency inside Turkey for the past 35 years.
"Turkey expects steps from the US befitting of a NATO ally and strategic partner," Erdogan said.
"Drying up the terrorist swamp in northern Syria is our top priority."
- 'Erdogan is serious' -
Turkish media outlets have often shown images in recent weeks of military convoys heading for the border area, carrying equipment and fighting units.
Turkey has twice carried out unilateral offensives into northern Syria against the Islamic State group and YPG, in 2016 and 2018 respectively.
Aldar Khalil, a top Kurdish political official in northeast Syria, told AFP on Monday that "Erdogan is serious and will embark on an attack at the first opportunity".
"If Turkey is not deterred and a consensus is not reached for an international decision to prevent it, it will definitely be on the offensive."
Khalil said the Kurds were "flexible" on the peace talks, and had offered a five-kilometre (three-mile) buffer zone, but that this had been rejected by Turkey, which wants to push the YPG much further back from the border.
Washington could stop any "attack with a single word... but it seems they don't want to pressure Turkey more than needed," he said.