US President Donald Trump and Turkish President Recep Tayyip Erdogan have discussed their security concerns in north-east Syria as US forces begin to withdraw.
The telephone call came after tensions were inflamed by a threat from Trump to "devastate" the NATO ally's economy if Ankara attacks US-backed Kurds in Syria.
Trump stressed "the importance to the United States that Turkey does not mistreat the Kurds and other Syrian Democratic Forces with whom we have fought to defeat ISIS," a White House statement said, referring to the Islamic State group.
The Turkish presidency said in a statement that the two men spoke about the possibility of establishing a safe zone in Syria, but did not mention the threat Trump tweeted at the weekend.
Turkish Foreign Minister Mevlut Cavusoglu earlier scolded Trump, telling a press conference in Ankara on Monday that "strategic partners do not communicate via Twitter and social media."
"Our channels are open," Cavusoglu said, adding that Trump has called Erdogan twice to talk about the need to coordinate the withdrawal of US troops from Syria with Turkey.
On Sunday, Trump tweeted: "Starting the long overdue pullout from Syria while hitting the little remaining ISIS territorial caliphate hard, and from many directions."
He also said it would "devastate Turkey economically if they hit Kurds." Trump also suggested the creation of a "20 mile safe zone" and cautioned Kurdish forces not "to provoke Turkey."
Trump announced the withdrawal of the 2,000 US troops from Syria in December, saying then that the years-long, hard-fought battle against Islamic State was over.
The move angered and surprised Washington's Kurdish and European allies. It also caused turmoil within the Trump administration and led to the resignation of Jim Mattis as defence secretary and Brett McGurk, the special envoy for the global coalition to counter Islamic State.
There have been mixed messages on the timeline of the US withdrawal from US Secretary of State Mike Pompeo, who wrapped up a Middle East tour on Monday, and US national security adviser John Bolton, who visited Turkey last week.
Turkey's top diplomat attributed Trump's conflicting statements to the "tremendous pressure ... especially from security agencies" on the US not to withdraw. "We know the latest tweet was a domestic policy message," he added.
Trump's suggestion of a safe zone had in fact first been proposed by Erdogan, said Cavusoglu.
"Threatening Turkey economically leads to nowhere," he added.
Last year, NATO allies Turkey and the US imposed tit-for-tat sanctions on each other's ministers, as well as tariffs on imports over the detention of Christian pastor Andrew Brunson, who was arrested on espionage and terrorism-related charges.
The row escalated a currency crisis in Turkey, with the lira losing more than 40 per cent of its value against the US dollar. A Turkish court lifted Brunson's house arrest and travel ban in October and he returned to the US.
Washington has relied on Kurdish forces as the most effective in the fight against Islamic State in Syria.
Ankara considers Syrian Kurdish militias - such as the People's Protection Units (YPG), which controls large areas of northern Syria on the border with Turkey - to be an extension of the outlawed Kurdistan Workers' Party (PKK) waging an insurgency within Turkey.
Last month, Erdogan said Turkey was delaying its planned military offensive in northern Syria but warned it was not "an open-ended waiting period."
