Turkey on Saturday urged the United States to withdraw personnel from a Kurdish-held town in northern Syria after Washington told Ankara it would stop arming a Syrian Kurdish militia that Turkey is fighting.
As Turkey's offensive in Syria entered its second week with new air strikes and artillery, Foreign Minister Mevlut Cavusoglu said it was "necessary for them (US) to immediately withdraw from Manbij", where Washington has a military presence.
Turkey launched operation "Olive Branch" on January 20 against the Syrian Kurdish People's Protection Units (YPG) militia in its western enclave of Afrin, supporting Syrian opposition fighters with ground troops and air strikes.
President Recep Tayyip Erdogan has threatened to expand the offensive against the YPG to Manbij, east of Afrin.
Relations between NATO allies Ankara and Washington have worsened since Turkey launched an operation, with the United States urging restraint and fearing an impact on the fight against the Islamic State (IS) extremist group.
One of the issues marring relations was the US supplying the YPG militia -- which has spearheaded the anti-jihadist fight -- with arms since last year in battles against IS.
Manbij itself was retaken from IS by the Kurdish-led, US-backed Syrian Democratic Forces in 2016 as part of a push that would later recapture the city of Raqa from the Islamist militants.
The Turkish presidency said US National Security Advisor H.R. McMaster "confirmed" to Erdogan's spokesman Ibrahim Kalin in a phone call late Friday that Washington would no longer "give weapons to the YPG".
Ankara says the YPG is a "terrorist" offshoot of the outlawed Kurdistan Workers' Party (PKK) which is proscribed as a terror group by Ankara and its Western allies.
"God willing we will crush them (terror groups) like a steam roller," Erdogan said Saturday during a speech in Istanbul.
The offensive came after the US-led coalition fighting IS announced this month that it is working to create a 30,000-strong border security force in northern Syria.
Erdogan at the time reacted strongly to the force which would be composed partly of YPG fighters, describing it as an "army of terror".
"The US must cut its ties with a terror organisation. It must take back the weapons it has given," Cavusoglu said, adding that Turkey "now wanted to see concrete steps taken" beyond verbal promises.
During their call, McMaster and Kalin cited Turkey's "legitimate security concerns" and agreed to coordinate closely in order to prevent misunderstandings.
The call came just days after Washington and Ankara bitterly contested each other's accounts of a telephone conversation between Erdogan and US President Donald Trump.
A White House statement said Trump urged Turkey to "limit its military actions", but a Turkish official said this was not an accurate reflection of the leaders' call.
There have been expressions of concern over the offensive from other Western allies including the European Union, France and Germany.
German officials also warned against tensions between the country's huge Kurdish and Turkish communities as hundreds of Kurds took to the streets of Cologne Saturday in protest over the military operation.
Germany is home to some one million Kurds and three million people of Turkish origin.
The Syrian Observatory for Human Rights monitoring group told AFP that the fighting was concentrated in the northwest part of Afrin region.
Turkish forces and allied Syrian rebels had taken a village and were making progress, albeit "slowly because of bad weather", Observatory head Rami Abdel Rahman said.
There were also continued air strikes and artillery fire Saturday, he added.
The Turkish military said "at least 394 terrorist organisation members were neutralised" in the operation thus far.
It was not possible to independently verify the toll.
The Observatory said that 111 Ankara-backed rebels and Kurdish fighters have been killed between both sides since last Saturday.
It said 38 civilians have been killed, mainly as a result of Turkish shelling, but Ankara strongly rejects such claims.
Turkey's AFAD emergencies agency head Mehmet Gulluoglu told reporters at the Oncupinar border crossing in the Kilis province that they were making plans for a camp to be established in the Syrian town of Azaz held by Ankara-backed rebels "in the face of a possible refugee influx from Afrin".