US Secretary of State Mike Pompeo says he is optimistic an agreement can be reached with Turkey to protect Kurdish fighters in Syria after the US leaves.
US forces in northern Syria have fought alongside a Kurdish militia against Islamic State (IS) militants.
Turkey, however, regards the People’s Protection Units (YPG) as a terrorist group and has vowed to crush it.
Mr Pompeo is touring the Middle East to try to reassure allies following President Donald Trump’s abrupt announcement last month that US forces would withdraw from Syria.
Talking to reporters in Abu Dhabi, Mr Pompeo said the US recognised “the Turkish people’s right and [Turkish President Recep Tayyip] Erdogan’s right to defend their country from terrorists”.
“We also know that those fighting alongside us for all this time deserve to be protected as well,” he said.
Mr Pompeo said he had spoken to Turkish Foreign Minister Mevlut Cavusoglu, adding: “Many details (are) still to be worked out but I’m optimistic that we can achieve a good outcome.”
Last week, President Erdogan angrily rejected calls by US National Security Adviser John Bolton for the Kurdish fighters to be protected.
He said such statements were “unacceptable”.
Mr Erdogan told MPs from his governing Justice and Development Party that the US did not know who the various Kurdish groups were, adding: “If the US evaluates them as ‘Kurdish brothers’ then they are in a serious delusion.”
Mr Bolton was on a visit to Ankara to seek guarantees over the Kurdish fighters, but President Erdogan declined to meet him.