The U.S.-led coalition in Syria is beginning to remove troops from Syria.

The coalition “has begun the process of our deliberate withdrawal from Syria,” said Colonel Sean Ryan, a spokesman for the U.S.-coalition fighting the Islamic State group. “Out of concern for operational security, we will not discuss specific timelines, locations or troop movements.”

Earlier this week, U.S. National Security Advisor John Bolton’s calls for the protection of the YPG Syrian Kurdish militia as a pre-condition to a U.S. troop withdrawal from Syria angered Turkish President Recep Tayyip Erdogan, causing the president to refuse to meet with the U.S. official.

The YPG is a crucial ally in Washington’s war against Islamic State but is considered by Ankara as a terrorist group linked to an insurgency inside Turkey.

Erdogan also warned that preparations were complete for a military operation against the YPG. “We will very soon mobilize to eliminate the terrorist organization in Syria,” he said.“If there are other terrorists who would attempt to intervene in our intervention then it is our duty to eliminate them as well,” Erdogan added. Turkish forces have been massing for weeks along the Syrian border.

Observers said the threat of a Turkish operation against the YPG in northeastern Syria, where around 2,000 U.S. soldiers are deployed, was the reason for U.S. President Donald Trump’s decision to withdraw from Syria. Once Trump announced his intention, Erdogan said Turkey would delay any operation until all U.S. forces left.

Ankara’s anger over preconditions announced by Bolton before any U.S. withdrawal, including security guarantees for the Kurdish militia, may have brought forward the timing of a strike against the YPG.

Last year, the Turkish currency collapsed after Trump hit Ankara with sanctions over the detention in Turkey of American pastor Andrew Brunson, who has since been released. Although the sanctions lasted only a few weeks, Turkey’s economy is now facing a recession. The lira fell sharply Tuesday on fears of renewed U.S.-Turkish tensions.

Turkish media are also reporting of divisions within Turkey’s military over the launching of a military operation into Syria in winter and before the full withdrawal of U.S. forces.

Former senior Turkish diplomat Aydin Selcen predicts Erdogan will now look to Trump to resolve the current tensions. “We have to wait to see what Mr. Erdogan has to say with Mr. Trump,” said Selcen, “because he (Erdogan) himself managed to persuade Mr. Trump that the United States will be leaving Syria. We have to wait to see what Mr. Erdogan and Mr. Trump have to say in the coming weeks.”

Turkish media are already blaming Bolton for the latest tensions, accusing him of going “rogue.” Washington is also facing criticism in Turkey for sending conflicting messages on its Syria policy.

Analysts, however, suggest Ankara is banking on shared regional interests and the personal chemistry of Trump and Erdogan to prevent a new crisis.