Donald Trump said the United States was lifting sanctions on Turkey and that Ankara has agreed to make the ceasefire with Kurdish-led forces along the border with Syria "permanent."
"The sanctions will be lifted unless something happens that we are not happy with," the president said on Wednesday, describing the creation of a "20-mile deep safe zone" as a "major breakthrough".
"By getting the ceasefire to stick, we've done something very, very special," he said, adding: "Tens of thousands of Kurds have been saved".
A small number of US troops will remain in the area "where they have the oil", Trump said, calling on nearby nations to help the two countries resolve their differences.
His comments came just a day after Turkish President Recep Tayyip Erdogan and his Russian counterpart Vladimir Putin announced that they had reached a deal to remove Kurdish forces to beyond 30 kilometres in some areas from the Turkish border. It followed a US-brokered ceasefire struck last Thursday to allow Kurdish forces to retreat from an agreed safe zone
Turkey launched a military offensive into northeast Syria on October 9 with the purported aim of creating a safe zone along the border to relocate the more than 3.6 million refugees it is hosting.
The offensive was launched within days of Trump pulling US troops from the area, held by the Kurdish-led Syrian Democratic Forces (SDF) and YPG, which are affiliated with Turkish Kurdish political groups Ankara considers to be terrorist organisations.
The incursion was widely condemned by Western countries, which had worked with Kurdish forces to dismantle the so-called Islamic State and led to sanctions against Turkey including an arms embargo from several EU member states.
In his address, Trump added that "ISIS is under very, very strict, lock and key" and that the "small number" of suspected IS fighters had been "largely recaptured".
"Now Turkey, Syria and others in the region must work to ensure that ISIS does not regain any territory. It's their neighbourhood," he said.
He also called on European countries to repatriate their foreign fighters.
Ahead of his speech, the American president had written on Twitter: "Big success on the Turkey/Syria Border."
"Safe Zone created! Ceasefire has held and combat missions have ended. Kurds are safe and have worked very nicely with us. Captured ISIS prisoners secured," he added.