A senior Republican senator on Saturday urged President Donald Trump to slow down the withdrawal of US ground troops from Syria until Islamist militants were defeated to avoid a "nightmare" for Washington's allies.
"I would hope that President Trump would slow the withdrawal until we truly destroy ISIS," Lindsey Graham told a press conference in Ankara, using an acronym for the Islamic State extremist group.
He warned any hasty pullout could lead to a "nightmare" scenario for Israel because of increasing Iranian influence in the war-torn country and for Turkey because of its national security concerns.
The South Carolina lawmaker was in Turkey from Friday for a two-day visit during which he met Turkish officials including President Recep Tayyip Erdogan and Foreign Minister Mevlut Cavusoglu.
His talks with Erdogan lasted for over two hours after which he was invited by the Turkish leader to a concert on Friday night by pianist Fazil Say.
Ankara welcomed Trump's announcement last month that the US would pull out its 2,000 military personnel from Syria but American officials and security experts have been more cautious, worried about withdrawing too early.
Graham, who as a member of the Senate Armed Services committee has frequently visited US troops in combat zones, said he believed the "goal of destroying ISIS is not yet accomplished".
Their defeat had been "accomplished territorially" but there were "thousands of ISIS fighters that lurk in Syria", Graham warned.
Four Americans, including two service personnel, were among those killed in a suicide attack this week claimed by the group in the key city of Manbij in Syria's north.
Washington has also expressed concern over Turkey's plans to launch a cross-border military operation against the US-backed Syrian Kurdish People's Protection Units (YPG) militia. Trump last weekend warned of devastating economic consequences for Turkey over any attack on Kurdish forces.
US support for the YPG has caused tension with Ankara which views the militia as a "terrorist offshoot" of the outlawed Kurdistan Workers' Party (PKK).
The PKK, which has waged an insurgency inside Turkey since 1984, is blacklisted as a terrorist organisation by Ankara, the US and the European Union.
Graham previously warned that "Kurds will get slaughtered" if the US withdrew immediately.
But on Saturday, the senator said the YPG's political branch, the Democratic Union Party (PYD), "is interlinked with the PKK" as he acknowledged Turkey's concerns over the militia.