The outgoing U.S. defense secretary has officially ordered the withdrawal of U.S. forces from Syria, according to CNN.

Citing an unnamed defense official, CNN reported that James Mattis signed the “execute order” for U.S. forces to leave the country, following U.S. President Donald Trump’s surprise announcement last week of the withdrawal.

The official gave no details on how and when the pullout of the some 2,500 troops will take place.

Last Wednesday Trump announced that the U.S. would withdraw its troops from Syria, following an Oct. 14 phone call with Turkish President Recep Tayyip Erdogan in which the two leaders agreed on the need for more effective coordination over the war-torn country.

The announcement reportedly took the Pentagon by surprise.

A day after Trump’s announcement, Mattis resigned, saying that his views were not aligned with those of the president.

Congressman and former presidential candidate Ron Paul has praised the widely criticized pullout decision.

Speaking on CNN, Paul said Sunday: "I am very proud of the president. This is exactly what he promised, and I think the people agree with him. We’ve been at war too long and in too many places ... spent several trillion dollars on these wars everywhere.”

Sharing Paul’s remarks on Twitter, Trump thanked the congressman for his support.

The withdrawal announcement comes on the eve of a possible Turkish military operation in northeastern Syria against the YPG/PKK terrorist group.

Since 2016, Ankara has successfully carried out two similar military operations in northern Syria.