President Donald Trump on Sunday tweeted that the "long overdue pullout from Syria" is starting, and threatened that the USA will "devastate Turkey economically" if they attack Kurdish forces in the war-torn country.
The troops in Syria have been supporting the Kurdish-led Syrian Democratic Forces fight ISIS, but with the militant group all but defeated, the United States president made the surprise announcement of a total U.S. withdrawal on December 19.
Trump's comments follow Turkish President Recep Tayyip Erdogan's pledge to take action against the YPG, which Turkey considers a terrorist organization linked to the outlawed Kurdish Workers' Party (PKK) within Turkey.
At the same time, Trump urged the Kurd-dominated Syrian Democratic Forces (SDF), which the United States trained and armed for years, not to "provoke" Turkey.
On Friday, the USA -led coalition said it had started the pullout, but officials later said only equipment, not troops, were going.
The previous week, Trump's National Security Advisor John Bolton had announced that Washington would withdraw its troops from Syria only after defeating ISIS and ensuring that the Kurds are safe.
He did not say how Turkey's economy would suffer if it attacked the YPG. Without giving any further details, he wrote "Create 20 mile (32 kilometers) safe zone".
Mr Pompeo said the withdrawal of USA troops from Syria was a "tactical change" but the mission to destroy Islamic State and counter Iran's influence remained the same.
The president defended his decision to withdraw troops, saying any remaining IS fighters could be attacked from an unspecified "existing nearby base".
"Russia, Iran and Syria have been the biggest beneficiaries of the long term USA policy of destroying ISIS in Syria - natural enemies".
But, he added, "we also know that those fighting alongside of us for all this time deserve to be protected as well".
"Stop the ENDLESS WARS!" he added.
President Donald Trump last month announced he would withdraw USA forces from Syria, declaring they had succeeded in their mission to defeat IS and were no longer needed.
Abdel Rahman said 16,000 people, including 760 Isis fighters, had fled the area since the start of December, though this marked the first time the SDF and the coalition provided buses, suggesting a deal struck between the warring sides.
On Saturday, more than 600 people were evacuated from the remaining IS holdout in eastern Syria, a monitor said, as US-backed fighters prepared for a final assault on the area.
A spokesman for the USA -led coalition said the SDF were making "great progress ... but the fight continues".