CAPITALS — The US is willing to work with Turkey to address its "legitimate" security concerns in northern Syria, Secretary of State Rex Tillerson has said.
He was speaking after Turkey's military incursion into northern Syria to fight the Kurdish YPG militia at the weekend.
Turkey sees the group as terrorists, but they have been crucial in a US-led coalition against ISIS.
Ankara said the US had to stop backing the YPG if they wanted cooperation.
Thousands of civilians in the northern Syrian region of Afrin are reportedly trying to flee as Turkey continues its ground offensive.
The UN Security Council has been meeting to discuss the operation, as well as the wider humanitarian situation in Syria.
Turkey says its troops have seized territory from the Kurdish militia.
It believes the fighters are an extension of the Kurdistan Workers Party (PKK), which has fought for Kurdish autonomy in Turkey for three decades. The YPG denies any direct links to the group.
Mr Tillerson said on Monday in London that the US recognised Turkey's "legitimate concerns" for its security, and its right to defend itself from terrorist elements. It called for restraint from "both sides".
He said the US had proposed measures to Turkey and others to try to stabilise the situation.
Turkey's Deputy Prime Minister Bekir Bozdag has expressed willingness to cooperate with the US, but said that it should first "stop arming terror groups and take back weapons already given".
Reports say the US is discussing with Turkey and others the possibility of a "security zone" being set up in north-west Syria.
Earlier Turkish President Recep Tayyip Erdogan vowed to "sort out" Afrin.
"We will take no step back," he said in a live television broadcast. "We spoke about this with our Russian friends; we have an agreement."