Trump must keep pledge to not arm YPG: Ankara

"The 'we will not give weapons' remark from a US president for the first time is important, but it will lose value if it is not implemented. It would be deceiving the world," deputy prime minister Bekir Bozdag said, commenting on Washington's pledge to end weapon provisions to Syrian Kurdish fighters.

On Friday, the White House said that US president Donald Trump had informed his Turkish counterpart that the US was adjusting the military support to partners on the ground in Syria.

"Mr Trump said he gave a clear order and that after this, weapons would not be supplied to the YPG (People's Protection Units), essentially he said this nonsense should have been ended earlier," Mevlut Cavusoglu, Turkish foreign minister said during a press conference in Ankara.

The Syrian Kurdish YPG has been at the forefront of the Syrian Democratic Forces, SDF, an alliance of Kurdish and Arab groups fighting the Islamic State group alongside the US-led coalition.

While the White House has been less explicit about the military's intentions towards the YPG, it confirmed that Trump had promised Erdogan of "pending adjustments to the military support provided to our partners on the ground in Syria, now that the battle of Raqqa is complete and we are progressing into a stabilization phase to ensure that [IS] cannot return".

Turkey views the YPG militia as an extension of the outlawed Kurdish Workers Party (PKK) and has been a cause for contention between the two countries. The PKK is a designated terrorist group by Ankara, the United States and the European Union.