Smoke rises from Ras al-Ain after an attack by Turkey earlier this week (Picture: PA).
Turkish forces have captured a key Syrian border town, according to the country's defence ministry.
Ras al-Ain has been heavily targeted by Turkey since its offensive into north-east Syria began on Wednesday.
Turkey's defence ministry tweeted that the centre of the town had been "taken under control".
The news of the town's capture marks the most significant gain of the incursion so far.
However, Kurdish forces deny this and appear to be holding out in some areas of the town.
The Kurdish-led Syrian Democratic Forces (SDF) released two videos it said to be from inside Ras al-Ain, showing fighters saying it is Saturday and they are still there.
According to the war monitor, Syrian Observatory for Human Rights, the fighting was ongoing as the Kurdish troops attempted to halt the Turkish advance.
The offensive follows the withdrawal of US troops from north-east Syria earlier this week.
US forces had been fighting alongside the SDF against so-called Islamic State (IS).
The decision faced widespread criticism - President Donald Trump was accused of endangering regional stability and risking the lives of the Syrian Kurdish allies who helped bring down IS in Syria.
The SDF was one of the US' closest ally in the fight against IS - 11,000 of its soldiers were killed during the five-year campaign.
US Defense Secretary Mark Esper said yesterday he was "greatly disappointed" by the actions of Turkey but admitted he was "not surprised".
Turkey, a NATO member, views the Kurdish forces as terrorists and wants to introduce a "safe zone" inside Syria.
On Friday, Turkish President Recep Tayyip Erdogan said Turkey will not stop until the Syrian Kurdish forces withdraw beyond a 20-mile line from the border.
United Nations officials say 100,000 Syrians have left their homes since the offensive began.
Turkey's state-run Anadolu news agency said Turkish-backed Syrian opposition forces had taken control of a motorway that connects the towns of Manbij and Qamishli.
Turkish troops also cut the route linking the north-eastern city of Hassakeh with Aleppo, Syria's largest city, according to the Syrian Observatory.