Turkish President Recep Tayyip Erdogan has said his military "won't stop" efforts to oust Syrian Kurdish fighters from Syria's north, as the leaders of Turkey, Russia and Iran met for talks on the conflict.
The three countries, which have teamed up to work for a Syria settlement despite their differences, reaffirmed their commitment to Syria's territorial integrity and the continuation of local ceasefires.
They called on the international community to provide more aid for the war-ravaged country.
Mr Erdogan, Vladimir Putin of Russia and Iranian President Hassan Rouhani were holding their second summit to discuss Syria's future since attending a similar meeting in Sochi, Russia, in November.
Mr Erdogan said Turkish troops, which last month took control of the north-western enclave of Afrin, would move eastward into Manbij and other areas controlled by the US-backed Peoples' Protection Units, or YPG, which Turkey considers to be terrorists.
"I say here once again that we will not stop until we have made safe all areas controlled by the (YPG), starting with Manbij," Mr Erdogan said.
He stressed that Turkey's fight against the YPG would not distract from efforts to eliminate the remnants of Islamic State group from the country.
Mr Erdogan said Turkish and Russian forces were discussing the possibility of establishing field hospitals in Tal Abyad to take care of people injured in attacks in the Damascus suburb of eastern Ghouta. He also spoke of plans to establish bakeries to help feed those in need.
The summit meeting came as the US said its military mission to eradicate Islamic State in Syria was coming to a "rapid end", but offered no timetable for withdrawal.
President Donald Trump had said earlier that the US's primary mission was to defeat IS and "we've almost completed that task".
Mr Trump said on Tuesday that he wants to bring troops home to start rebuilding the US.
But his comments conflict with views of his senior military advisers, some of who spoke at a separate event in Washington about the need to stay in Iraq and Syria to finish off the militant group, which once controlled large areas of territory in both countries.
Asked about the possible US pullout, Mr Rouhani said the US move from Syria is an excuse for soliciting money from countries that want them to remain there.
He said: "One day they say they want to pull out of Syria ... then it turns out that they are craving money. They have told Arab countries to give them money to remain in Syria."
Russia and Iran have provided crucial support to President Bashar Assad's forces, while Turkey has backed the rebels seeking to overthrow him.
The three nations have sponsored several rounds of talks between the Syrian government and the opposition, and brokered local truces in four areas, helping to reduce hostilities.
Meanwhile, the Russian military said on Wednesday that it expects a rebel evacuation from the suburbs of the Syrian capital to be completed in the coming days.
The Russian Defence Ministry and Syrian rebels struck a deal on Sunday for the Army of Islam, the biggest opposition group in the Damascus suburbs of eastern Ghouta, to leave the area for the rebel-controlled north.
The rebels were still leaving the town of Douma, but the evacuation was expected to wrap up in the coming days, said Colonel General Sergei Rudskoy of the Russian General Staff.
Earlier, Russia's Defence Ministry said more than 3,000 rebels and their family members had left Douma since Sunday.
The evacuation comes after a five-week government offensive in February and March that killed hundreds of people and caused catastrophic damage in the besieged suburbs.