The US military has announced that the order to pull the American forces out of Syria has been signed, after the US and Turkish presidents agreed on subsequent measures.

President Donald Trump unexpectedly announced on Wednesday that the US would be pulling all its 2,000 forces out of Syria. He also claimed victory over the Daesh Takfiri terror outfit in the war-torn state.

"The execute order for Syria has been signed," a US military spokesperson told AFP when asked about the pullout order, without elaborating.

The news came after Turkish President Recep Tayyip Erdogan said he had spoken with Trump by phone on Sunday and "agreed to ensure coordination between their countries' military, diplomatic and other officials."

Earlier in the day, Trump tweeted that he and Erdogan had "discussed (Daesh), our mutual involvement in Syria, & the slow & highly coordinated pullout of US troops from the area."

Ankara welcomed Washington's decision to withdraw from Syria. Observers say it appears that the US has chosen to strengthen its alliance with Turkey at the expense of its Kurdish allies in Syria.

Washington has long been supporting the so-called Syrian Democratic Forces, an anti-Damascus coalition of Kurdish militants, as its most effective partner in Syria.

Ankara, however, views the SDF as a terrorist organization and an extension of the outlawed Kurdistan Workers’ Party (PKK) that has been seeking an autonomous Kurdish region since 1984.

On Sunday, French President Emmanuel Macron rebuked Trump over his decision to withdraw troops from Syria, saying "an ally must be reliable."

France, a leading member of the US-led coalition, has said it would keep troops in Syria. France’s pronouncement of support came even as the SDF said it would stop its alleged fight against Daesh terrorists.

Trump's decision has sparked turmoil within his administration, prompting the resignation of Defense Secretary Jim Mattis and Brett McGurk, the special envoy to the so-called anti-Daesh coalition.

Trump later named Deputy Secretary of Defense Patrick Shanahan as the acting Pentagon chief, saying he will replace Mattis starting January 1, earlier than previously scheduled.

Trump’s decision on Syria was reportedly preceded by the deployment of forces from its Arab allies to Syria.

'UAE, Saudi, Sudanese troops deployed to Syria'

The Arabic-language al-Manar newspaper reported on Sunday that forces from the UAE, Saudi Arabia, Sudan and other nations of the so-called axis of moderation had been deployed to the east of Euphrates River in Syria, adding that the move came in coordination with the US and France.

The paper quoted informed sources as saying that the deployment took place before Trump’s announcement of the pullout plan. It said a number of Emirati and Saudi officers had been deployed to the region about a month before.

Terrorists sent to Africa, Iran's neighbors: TV

The sources also told al-Manar that the US had provided terrorists operating in the region, most of them Daesh members, with additional weapons, and transferred hundreds of them to areas in North Africa, Libya and Egypt's Sinai as part of a process to redistribute them after their heavy losses against Syrian army troops.

The report said that Washington had also sent a number of terrorists to Azerbaijan, Afghanistan and areas near the Iranian and Russian borders.

Washington and Arab allies, the newspaper said, claim that such moves would diminish the perceived threat posed by the presence of Iranian military advisers and Lebanon’s Hezbollah resistance movement in Syria.

Iran has been offering military advisory support to Syria at the request of the Damascus government, enabling its army to speed up its gains on various fronts against terror outfits.

Hezbollah forces have also been assisting the Syrian government on the ground to clear areas bordering Lebanon from terrorist groups.