Flanked by vice president Mike Pence and secretary of state Mike Pompeo, Mr Trump took credit for a Russia-backed truce between Ankara and Kurdish forces, saying that the United States had saved thousands of lives.
He later said that his country had spent $8 trillion (£6.2 trillion) on unsuccessful wars in the Middle East, where too many American service members had died. He vowed Washington would pursue “a different course”.
“The government of Turkey informed my administration that they would be stopping combat and their offensive in Syria ... I have therefore instructed the secretary of the treasury to lift all sanctions,” he said from the White House.
“We reserve the right to reimpose crippling sanctions should Turkey fail to honour its obligations,” he added.
Mr Trump later defended the decision to pull hundreds of troops out of Syria saying that other nations in the region “must ultimately take on the responsibility”.
“Let someone else fight over this long-bloodstained sand,” he said.
Turkey launched a controversial cross-border incursion to push back Syrian Kurdish fighters in northeastern Syria, where Ankara hopes to build a “buffer zone”.
More than 176,000 people have been displaced and about 500 Isis fighters gained freedom during the two-week long conflict.
In response, Mr Trump halted negotiations on a trade deal with Turkey, raised steel tariffs back up to 50 per cent and imposed sanctions on three senior Turkish officials and Turkey’s defence and energy ministries.
But he was originally accused of “green-lighting” the offensive after ordering the bulk of approximately 1,000 US troops in Syria to withdraw and not hinder Turkey’s imminent attack.
The US pullout was seen as an abandonment of Kurdish fighters, who have incurred thousands of casualties as they fought with US forces against Isis.
The Kurds were forced to strike a deal with Syrian president Bashar al-Assad who deployed government forces to secure the border.
On Tuesday Turkish president Recep Tayyip Erdogan and Russian president Vladimir Putin agreed to a deal that would see Turkey halt its offensive if Kurdish forces withdrew to outside a 30km-wide buffer zone and Russia and Turkey launched joint patrols.
It sparked some criticism in Syria where Kurdish civilians told The Independent they fear a backlash from Turkey-backed forces while others expressed concerns about the advancing regime.
The agreement followed a US-brokered ceasefire that expired Tuesday night.
Mr Trump took credit for Tuesday’s deal, saying: “We’ve done a good job, we’ve saved a lot of lives”.
Syrian Kurdish commander Mazloum Abdi later thanked Mr Trump, issuing a statement which said the truce with Turkey would not have been possible without his efforts.
Mr Trump also used Wednesday’s speech to confirm that the majority of US troops would leave Syria for western Iraq, but a small contingent would stay to guard oil fields against groups like Isis.
However, US troops do not have permission to stay in Iraq permanently.
Iraq’s defence minister, Najah al-Shammari, said on Wednesday American soldiers must leave the country within four weeks.
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