Officials said the president was withdrawing US troops from Syria because Daesh has been defeated there.
The Trump administration will withdraw all of the approximately 2,000 American troops in Syria, according to a US official, as the White House declared victory on Wednesday in its mission to defeat Daesh terrorists there.
The decision came after a phone call between US President Donald Trump and his Turkish counterpart Recep Tayyip Erdogan last Friday.
A senior US official told Reuters that Trump had informed the Turkish president about his decision.
Planning for the pullout has begun and troops will begin leaving as soon as possible, said the official, who was not authorised to publicly discuss military planning and spoke on condition of anonymity.
Trump said American forces no longer were needed in a country torn apart by long-running civil war.
But officials have said in recent weeks that pockets of Daesh terrorists remain. US policy has been that American forces would stay in place until the extremists were eradicated.
In addition, Pentagon and other officials have said that US troops were countering Iran-backed militants in Syria, which was an expansion of the US mission.
Trump said on Twitter: "We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency."
We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency.— Donald J. Trump (@realDonaldTrump) December 19, 2018
His tweet followed a series of news reports that the US was preparing to withdraw its troops from Syria. The news was first reported by The Wall Street Journal.
TRT World's Sally Ayhan has the latest from Washington.
A US official told Reuters the US plans to pull military forces out of the country once the final stages of the last operation against Daesh is complete, and that the time-frame for the troop pullout is expected to be between 60 to 100 days.
Pentagon said in a statement that it has started the process of returning US troops home from Syria as "we transition to the next phase of the campaign".
"Coalition has liberated the ISIS-held territory, but the campaign against ISIS is not over", it added.
TRT World's Hasan Abdullah reports on Turkey's reaction from Ankara.
Decision draws an international reaction
Israel's Prime Minister Benjamin Netanyahu in a statement said he had spoken over the past two days with the US president and secretary of state about their intention to withdraw US forces from Syria.
"They made clear they have other ways to have influence in the area," Netanyahu said, adding that Israel will ensure its own security.
Russian Foreign Ministry said the decision to withdraw US troops from Syria creates prospects for political settlement.
In its response, Britain said that Daesh remained a threat even though it held no territory.
“Much remains to be done and we must not lose sight of the threat they pose. Even without territory, Daesh will remain a threat,” the British Foreign Office said in a statement.
“As the United States has made clear, these developments in Syria do not signal the end of the Global Coalition or its campaign. We will continue to work with members of the coalition on achieving this.”
Retired Brigadier General of the US army, Mark Kimmitt discusses the decision.
Reports of an abrupt withdrawal drew quick criticism from Congress Senator Marco Rubio who said a full and rapid removal of troops would be a "grave error with broader implications" beyond the fight against Daesh.
Republican Senator Lindsey Graham also parcelled out a caution in response, saying withdrawing US troops from Syria would "be a big win for ISIS, Iran, Bashar al Assad of Syria, and Russia."
Trump's tweet also drew criticism from British defence minister Tobias Ellwood who tweeted "(Islamic State) has morphed into other forms of extremism and the threat is very much alive."
I strongly disagree.— Tobias Ellwood (@Tobias_Ellwood) December 19, 2018
It has morphed into other forms of extremism and the threat is very much alive. https://t.co/wrRMTBJ4tX