Assad forces 'legitimate targets' if they back YPG, says Turkey

Touching on Turkey's ongoing "Operation Olive Branch" into Afrin Kalın said Ankara believes that the YPG is "trying to turn Afrin into a new terrorist headquarters", similar to how the outlawed Kurdistan Workers' Party (PKK) has used the Qandil Mountains in northern Iraq.

According to Reuters, a spokesman for Turkish President Tayyip Erdogan stated that pro-Assad forces retreated to east of Aleppo, and warned that an attempt at entering Afrin will have serious consequences.

But on Tuesday state media reported that members of the "Popular Forces" had arrived in Afrin to "support the locals against the aggression waged by the Turkish regime" and to confront IS, which has no known presence in the area.

Paramilitary forces aligned with Syrian President Bashar al-Assad arrived in Afrin on Tuesday.

On Jan. 20, the Turkish Armed Forces, together with the Free Syrian Army, launched the Operation Olive Branch in Afrin, Syria.

However, Istanbul has denied that pro-Assad forces in Afrin are working in coordination with Damascus.

"Yesterday, we have already agreed on these issues in talks with [Vladimir] Putin and [Hassan] Rouhani", Erdogan said.

"They would pay a heavy price for it", Erdogan warned.

Meanwhile, Russia had called for direct negotiations between Damascus and Ankara to resolve the Afrin crisis.

The YPG played a key role in fighting ISIS, effectively pushing it out of much of northern Syria, but has now been abandoned by former allies like the United States.

The government was asked for military help by a Kurdish militia that has been trying to repel an offensive by Turkish troops and allied Syrian rebels. Turkey began its assault last month to drive out the YPG, which it deems a security threat along its border akin to the Kurdish PKK insurgency on its own soil.

Turkish troops entered Syria on January 20 to expel Kurdish YPG fighters from the border area, viewing them as an extension of the Kurdish PKK separatist group that Turkey has fought for decades.

The YPG has denied having political or military ties with the PKK but admits it is inspired by democratic confederalism. However, the YPG still holds most of the Afrin region including its central town.