President Recep Tayyip Erdogan on Friday said Turkish forces and allied rebels could enter the centre of the Kurdish-held Syrian town of Afrin “at any moment”, a day after the capture of another key strategic town.

“Now our objective is Afrin... As of now, we have Afrin encircled. We can enter Afrin at any moment, God willing,” Erdogan told his ruling party in Ankara, a day after Turkish forces took control of the town of Jandairis west of Afrin.

“The operations in Afrin will continue until this swamp of terror is dried,” he warned.

Ankara on January 20 launched operation “Olive Branch” in the Afrin region of northern Syria against the Kurdish People's Protection Units (YPG) militia who control the area but Turkey regards as a terror group.

Despite encountering fierce resistance ─ which has seen 42 Turkish troops lose their lives ─ the Turkish military and its Syrian allies appear to have gained new momentum in the last weeks.

The capture of Jandairis ─ one of the key centres in the region other than Afrin itself ─ was seen by analysts as giving Ankara a clear path towards its main target.

But the operation has ratcheted up tensions with the United States (US), pitting Turkey's army against a militia force allied with its fellow NATO member in the battle against Islamic State (IS) militants.

Erdogan also reaffirmed his previous vows that Turkey would not limit itself to clearing the Afrin region of the YPG, saying it wanted to carry on to the town of Manbij to the east and then to the Iraqi border.

“Today we are in Afrin and tomorrow we will be in Manbij. And the next day we will ensure that terrorists are cleared east of the Euphrates River up to the Iraqi border,” he said.

Manbij is regarded as a particularly delicate issue as the US ─ unlike in Afrin ─ has a presence there, raising the prospect of a direct clash with Turkey.

On a visit to Ankara last month, US Secretary of State Rex Tillerson said that Turkey and the US had to solve the tensions surrounding Manbij as a “priority”.