US Secretary of State Rex Tillerson visited Turkey on Thursday, amid tensions between the nations and joint efforts to defeat Islamic State, and said the future of Syrian President Bashar al-Assad would depend on the Syrian people.
"The longer term status of President Assad will be decided by the Syrian people," Tillerson said in a press conference alongside Turkish Foreign Minister Mevlut Cavusoglu.
Al-Assad's future has been one of the most divisive issues in repeated international efforts to find a solution to the Syrian conflict.
The former US administration of Barack Obama had said al-Assad had no legitimacy and the Syrian opposition insists he must step down. Al-Assad is backed by Russia.
The US' top diplomat sidestepped some of the thornier issues, includes Turkey's opposition to Washington allying with the Syrian Kurdish YPG militia in the ongoing war against Islamic State in Syria.
The group has become the most effective fighting force in terms of seizing and controlling territory from Islamic State, but Turkey says it has links to Kurdish militants on its own territory.
The US-backed Syrian Democratic Forces (SDF), which is comprised of Arab units alongside the YPG, are in the process of encircling al-Raqqa, the Islamic State's de-facto capital in Syria.
Tillerson said the aim was for local forces to eventually have control over the city.
Tillerson said there was "no space" between Turkey and the US about the need to defeat Islamic State. He conceded there are "difficult choices that have to be made."
He said there were "candid conversations" with President Recep Tayyip Erdogan and other officials.
Cavusoglu again raised the issue of the cleric Fethullah Gulen, whom Ankara blames for orchestrating a failed coup by officers in the military last year. Gulen, who lives in the US, denies the charges.
This week, the US arrested a top executive at Turkey's state-owned Halkbank over allegations he helped evade nuclear-related sanctions on Iran, a matter that also came up.
Cavusolgu accused the US prosecutor who launched the Halkbank case and a related case of Iranian-Turkish gold-trader of having ties to Gulen, and said the matter was a "political process."
The prosecutor, Preet Bharara, was fired by the new US administration as part of a shake-up as it took over.