Erdogan says Turkish army will crush Kurds in northern Syria's Afrin

Turkish troops close to the Aleppo province's Afrin will crush Kurdish fighters in the north-western Syrian city, President Recep Tayyip Erdogan vowed on Saturday.

It comes after Turkish forces fired shells at several Kurdish villages in the canton on Saturday.

Turkish forces were poised to move into Idlib province as monitors, as part of a deal with Russia and Iran to create de-escalation zones in Syria.

Instead, they moved to areas in the north close to Afrin where the People's Protection Units (YPG) were allegedly looking to link the Syrian enclave to a larger Kurdish region to the east.

Erdogan said this military intervention had prevented the Kurdish forces from creating a "terror corridor" and promised to crush any new Kurdish insurgencies.

"If the terrorists in Afrin don't surrender we will tear them down," Erdogan told members of his party on Saturday.

In 2016, Turkey sent in troops and allied Syrian rebel fighters into northern Syria as part of the Euphrates Shield operation.

Ankara said it was to tackle the Islamic State group who had been firing shells over the border, but soon the Turkish and Syrian fighters were confronting Kurdish forces who had increased their territory in the area.

"With the Euphrates Shield operation we cut the terror corridor right in the middle. We hit them one night suddenly. With the İdlib operation, we are collapsing the western wing," Erdogan said on Saturday, according to Reuters.

Euphrates Shield saw Turkish and Syrian rebel forces capturing the iconic town of Dabiq from IS, but also butt heads with Kurdish fighters in Manbij.

Erdogan said that conflict was far from settled.

"In Manbij, if they break the promises, we will take the matter in our own hands until there are no terrorists left. They will see what we'll do in about a week," he said.

Turkey has been wary of the advance of the Kurdish-led Syrian Democratic Forces in northern Syria against IS. 

Ankara fears these territories could be used as a base for fighters in the Kurdistan Workers' Party (PKK) to attack troops in Turkey. 

Southern Turkey has seen a decades-long insurgency by Kurdish separatists and believe the Syrian YPG are part of the PKK.

Tensions have also increased between Turkey and the US over Washington's support for the Syrian Democratic Forces.

"The US sent 4,900 trucks of weapons in Syria. We know this. This is not what allies do," Erdogan alleged on Saturday. "We know they sent 2,000 planes full of weapons."