Erdogan said Saturday that any venture in the region "has no chance of success" if Turkey has no consent in it, referring to the PYD/PKK terror group's effort to settle in Syria's northern regions along the Turkish border.
Turkey regards the Kurdish YPG forces who control Afrin as a terrorist group with links to the PKK, which has long battled for autonomy in Turkey's southeast. The eight-month combat effort officially ended in March 2017.
A YPG spokesman in Afrin said clashes erupted after midnight between his unit and Turkish troops near the border with Turkey.
Erdogan said the new operation into Afrin would be an extension of Turkey's 2016 incursion into northern Syria, which aimed to combat IS and stem the advance of USA -backed Kurdish forces.
"In the coming days, God willing, we will continue with Afrin [operation] - that we started first with Euphrates Shield Operation - to purge terrorism from our southern borders", Erdogan said in his speech at the provincial congress meeting of his ruling Justice and Development (AK) Party in the central Anatolian Tokat province.
Erdogan added that he's waiting for backing from allies, without elaborating.
He criticized the United States for arming YPG and Arab fighters in the Syrian Democratic Forces, which drove ISIS out of Raqqa and other parts of Syria.
"They will be providing border security through professionally securing checkpoints and conducting counter-IED operations", the office said, adding that coalition and SDF forces were still engaging remaining ISIL pockets in Deir Ezzor province.
YPG will fight to "defend our gains, our territories", Roj said.
She called Turkey's operation against Afrin a "violation" that "undermines global efforts to reach a political solution in Syria".
Since December, Ankara has reinforced its southern border by sending armoured vehicles, tanks, and heavy machine guns, the Hurriyet daily cited sources as saying.
Turkey and its western allies, including the U.S., consider the PKK a terrorist organisation.
Turkey has been working closely with Russian Federation and Iran to end the almost seven-year Syrian conflict despite Moscow and Tehran supporting Syrian President Bashar al-Assad and Ankara supporting the anti-Assad opposition.
The Turkey-PKK conflict has killed an estimated 40,000 people since 1984, including more than 3,300 state security forces, militants and civilians since the resumption of hostilities in July 2015.