President Recep Tayyip Erdogan on Friday threatened to expand Turkey's offensive in Syria against a Kurdish militia, despite rising concern and calls for restraint from the US and other Western allies.
In the seventh day of the operation against the Syrian Kurdish People's Protection Units (YPG) militia, Erdogan vowed to "clean up" the Syrian city of Manbij.
The United States has raised concerns over the deadly offensive, and analysts say direct military conflict between the two NATO powers is possible since the US has a military presence in Manbij.
Turkey launched operation "Olive Branch" against the YPG on Saturday, supporting Syrian rebels with ground troops, air strikes and artillery fire.
While the YPG is still working closely with Washington against the Islamic State (IS) extremist group in Syria, Ankara views the YPG as a terror organisation allied to the outlawed Kurdistan Workers' Party (PKK) inside Turkey.
The PKK is blacklisted by Ankara and its Western allies as a terror outfit.
Erdogan vowed in a speech in Ankara that Turkey would "continue our fight until there is no terrorist on our border", but did not elaborate.
He said the operation would last until "we reach our goals," adding: "Afterwards we will, as promised, clean up Manbij of terrorists."
But Erdogan and Foreign Minister Mevlut Cavusoglu on Friday insisted Turkey was not intending to occupy Afrin and would return the region to its "real" owners.
- US ties 'teetering on brink' -
Tensions between Ankara and Washington are already high but the offensive has added further strain to their relationship. The two sides disagreed about the content of telephone talks between Erdogan and US President Donald Trump on Wednesday.
Washington said Trump had urged Turkey to "limit its military actions" but a Turkish official said the US statement did "not accurately reflect the content" of the call.
Erdogan criticised Turkey's allies, including the United States, which he said called for the operation to be "short" and "limited" in scope, referring to previous interventions.
"How long has Afghanistan lasted? Nearly 20 years. How long has it (the conflict) lasted in Iraq? Nearly 18 years!" he thundered.
Washington has more than 2,000 special forces and support troops inside Syria, mainly east of the Euphrates in an area also controlled by the YPG but separate from Afrin, which is west of the river.
According to Anthony Skinner, director of MENA at global risk consultancy Verisk Maplecroft, "direct military conflict" between Turkish and US forces is possible because of Erdogan's threats to expand the campaign to Manbij.
"Turkish-US relations are teetering on the brink of a precipice," Skinner added.
The European Union has also expressed concern over the Turkish intervention in Syria, which is further complicating the war that has claimed more than 340,000 lives since 2011.
- 'Nothing is left' -
Turkey continued shelling YPG positions in Afrin on Friday, state-run news agency Anadolu reported.
Speaking to AFP in the Syrian town of Azaz held by pro-Ankara fighters, Syrian rebel Ali Yassin said the goal was "to cleanse this region of terrorists", adding: "We do not want terrorists in our country."
Erdogan said "343 terrorists have been neutralised" during the operation so far. It was not possible to independently verify the toll.
Three Turkish soldiers have been killed since the start of the offensive, while the Syrian Observatory for Human Rights has said 58 Ankara-backed Syrian rebels and 53 US-backed Syrian Democratic Forces and YPG fighters had been killed.
The SDF is an umbrella grouping composed mainly of YPG fighters.
The Observatory has said 38 civilians have been killed mainly as a result of Turkish shelling but Ankara strongly rejects such claims, saying it is doing everything possible to avoid civilian casualties.
Thousands of people have reportedly fled the Afrin region's border towns, many of them to Afrin city, after fleeing Turkish artillery fire.
"The shells hit every neighbourhood, they hit the generators and the bakery. Nothing is left," Merhi Hassan said, after fleeing his native Jandairis, a border town.
- Afrin urges Syria to intervene -
Afrin's executive council on Thursday called on Syria to intervene to stop Turkish planes.
Kurdish fighters and government troops have largely stayed away from each other since then, albeit with short-lived clashes in the cities of Hasakeh and Qamishli.