Turkey has mobilised thousands of Free Syrian Army (FSA) rebels to a border province with Syria, as part of a planned offensive against Kurdish fighters, according to Turkish media.

Anadolu news agency reported that the Ankara-backed FSA rebels were taken "under extensive security" in a convoy of at least 20 buses, from the province of Kilis to another southern province of Hatay.

Al Jazeera's Stefanie Dekker, reporting from Antakya in Turkey, said as many as 15,000 FSA rebels are also being mobilised east of Afrin, a Syrian border town, as part of the operation.

"The situation in Afrin is heating up. There's been an increasing shelling from Turkey into Afrin," Al Jazeera's correspondent said.

"This is in line with the political rhetoric coming out of Ankara over the last week or so."

On Friday, Turkey's defence minister said his country would go ahead with its military offensive in Afrin, saying Syrian Kurdish fighters there pose a "real" threat to his country.

Turkey considers the armed Kurds within its territory, as well as those in neighbouring countries, as "terrorists".

Ankara fears the establishment of a Kurdish corridor along its border.

The Turkish army has intensified shelling on Afrin in recent days and said a ground assault could happen soon, similar to the 2017 Operation Euphrates Shield, in which Turkish-backed FSA rebels cleared a large part of northern Syria of armed fighters.

According to estimates, there are between 8,000 to 10,000 Kurdish fighters in the Afrin area of Syria.

Turkey considers Syria's Kurdish Democratic Union Party (PYD) and its armed wing, the YPG, "terrorist groups" with ties to the banned Kurdistan Workers' Party (PKK), which has waged a decades-long fight inside Turkey.





Russian consent

The mobilisation of the FSA also comes as Russia has reportedly started moving its military observers away from northwestern Syria.

Russia controls the airspace over Afrin. Moscow's military intervention in 2005 turned the war in favour of Syrian President Bashar al-Assad.

Turkey's chief of staff and head of intelligence were in Moscow on Thursday and Friday, to try and see whether Russia gives the green light on the operation, Al Jazeera's Dekker said.

"It's all about politics," she said. "It's very complicated, and you are seeing different players trying to carve up different parts of Syria, expanding their spheres of influence."

Meanwhile, Stephane Dujarric, spokesman of UN Secretary-General Antonio Guterres, warned against more military activities in Syria.

"We've seen the reports of shelling in Afrin. We reiterate our call on all concerned parties to avoid further escalation and any acts that could deepen the suffering of the Syrian people," Dujarric said.

"All parties must ensure protection of civilians at all times, under any circumstances."

The US had also urged Turkey to avoid taking action against the Kurdish rebels, urging Ankara to keep its focus on the Islamic State of Iraq and the Levant (ISIL, also known as ISIS).

There have been reports that the US was also trying to recruit Kurdish fighters in Syria to fight against ISIL.

In response, Turkey warned that its relations with the US would be "irreversibly harmed" if Washington moves to form the 30,000-strong army in the north of Syria.