The US will play no role in an imminent Turkish operation against Kurdish forces in north-eastern Syria, the White House has said, in a major shift.
Turkey wants to clear Kurdish militiamen – whom it regards as terrorists – away from the border.
The Turks would become responsible for all Islamic State (IS) group prisoners in the area, the US statement said.
Kurdish YPG fighters have until now received strong support from the US, which has hundreds of troops in Syria.
In January, President Trump threatened to “devastate Turkey economically” if it attacked Kurdish forces following a planned US pullout from Syria.
However, the White House statement issued on Sunday makes no reference to the YPG, which has played a leading role in defeating IS – also known as Isis – in Syria.
The statement follows a phone call between President Donald Trump and Turkish President Recep Tayyip Erdogan.
It came a day after Mr Erdogan said the Turkish incursion would soon take place.
What did the White House say?
“Turkey will soon be moving forward with its long-planned operation into Northern Syria,” the statement said.
“The United States Armed Forces will not support or be involved in the operation, and United States forces, having defeated the ISIS territorial ‘Caliphate’, will no longer be in the immediate area.”
The White House statement also said that Turkey would take over all responsibility for Islamic State (IS) group fighters captured over the past two years.
“The United States government has pressed France, Germany, and other European nations, from which many captured ISIS fighters came, to take them back but they did not want them and refused.
“The United States will not hold them for what could be many years and great cost to the United States taxpayer.”
What’s the background?
During his phone call with Mr Trump, Mr Erdogan expressed frustration at a lack of progress in establishing a “safe zone” in north-eastern Syria along the border with Turkey, which the Nato allies had agreed in August.
The YPG was a major part of the Syrian Democratic Forces (SDF), the US-supported force that defeated IS in Syria.
Turkey also wants to move up to two million Syrian refugees from its territory into the zone. Turkey currently hosts 3.6 million Syrians sheltering from the conflict.
Why does Turkey regard the YPG as terrorists?
Turkey considers the YPG an extension of the banned Kurdistan Workers’ Party (PKK) which has fought for Kurdish autonomy in Turkey for three decades.
The YPG denies any direct organisational links to the PKK.
Turkey has previously condemned the US for supporting the YPG.