Trump's promise to stop arming Kurds comes as Russia and Iran seek to control country's post-war fate
US concession to Turkey reflects concerns over Syria
President Donald Trump's assurance that the United States will stop arming Syrian Kurds eases tensions with Turkey as both countries prioritise their long-term objectives in post-war Syria ahead of a new round of peace talks starting this week.
Washington's promise to not send any more weapons to the Kurdish People's Protection Units (YPG) is key concession to Ankara. But without it Turkey, a Nato ally, would have moved closer to Iran and Russia, who are battling to save Syrian president Bashar Al Assad's regime.
The US pledge was revealed by Turkish foreign minister Mevlut Cavusoglu, who said it was made during a phone call between Mr Trump and his Turkish counterpart, Recep Tayyip Erdogan, during a phone call on Friday.
Mr Trump told Mr Erdogan he had "given clear instructions" that the Kurds would receive no more weapons "and that this nonsense should have ended a long time ago", Mr Cavusoglu said.
The YPG has been the main US ally fighting ISIL in Syria for more than three years, but Turkey says it is an extension of the outlawed Kurdistan Workers Party (PKK), a group it has been fighting for decades in the country's south-east. Turkey also fears the establishment along its border of a contiguous, Kurdish-held canton in northern Syria.
The White House confirmed the US president's assurance to Mr Erdogan in a cryptic statement about his phone call with his Turkish counterpart. It said Mr Trump had informed Mr Erdogan of "pending adjustments to the military support provided to our partners on the ground in Syria".
The White House statement called the move "consistent with our previous policy" and noted the recent fall of Raqqa, ISIL's self-declared capital that was liberated by a largely Kurdish force last month.
"We are progressing into a stabilisation phase to ensure that [ISIL] cannot return," it said.
Turkey is part of the US-led anti-ISIL coalition but launched its own intervention in northern Syria last year, battling ISIL extremists but also the Kurdish forces for several months before ending its operation.
The White House said Mr Trump and Mr Erdogan had also discussed the importance of the eighth round of UN-backed peace talks beginning in Geneva on Tuesday.
Syria has been ensnared in civil war between Mr Al Assad and an array of armed groups since 2011, and the chaos allowed ISIL to seize large areas of the east.
Both Washington and Ankara have backed rebel groups against Mr Al Assad and share an interest in countering Russian and Iranian influence in Syria and in shaping the country's post-war future.
But Turkey is now also part of a parallel and potentially rival political process organised by Russia in the Kazakh capital Astana.
On Wednesday, Mr Erodogan met Russian president Vladimir Putin and Hassan Rouhani of Iran in the Russian resort of Sochi to discuss the fate of Mr Al Assad and the Geneva talks.
This could explain the timing of Mr Trump's phone call to Mr Erdogan.