ANKARA: Turkey has sent special forces into the Syrian region of Afrin in anticipation of urban fighting in its operation against a Kurdish militia, Ankara said on Monday.

Turkey on January 20 started an offensive supporting Syrian rebels against the US-backed People's Protection Units (YPG) militia in the western enclave of Afrin.

"Deploying special forces is part of the preparation for a new fight that is approaching," Deputy Prime Minister Bekir Bozdag, also government spokesman, said.

An unknown number of gendarmerie and police special forces entered the region on Sunday night, state news agency Anadolu said.

Bozdag said the fight continued in villages and countryside far from Afrin's centre.

"The fight will shift to places where there are civilians, as the area (of fighting) narrows," Bozdag said during an interview with NTV broadcaster.

The deputy prime minister said the special forces had experience fighting against militants in residential areas of Turkey "without harming civilians".

Turkey views the YPG as a "terrorist" Syrian extension of the Kurdistan Workers' Party (PKK), which has been waging an insurgency against the Turkish state since 1984.

The PKK is blacklisted as a terror group by Ankara, the United States and the European Union.

But the YPG has been working closely with the US against the Islamic State extremist group in Syria, much to Ankara´s infuriation.

President Recep Tayyip Erdogan last week said Turkey would lay siege to the centre of the town of Afrin "in the coming days".

The UN Security Council on Saturday adopted a resolution on a ceasefire in Syria to allow for humanitarian aid deliveries and medical evacuations after intense regime bombardment of the rebel-held enclave of Eastern Ghouta, which killed hundreds.

French President Emmanuel Macron told Erdogan during a telephone call on Monday that the ceasefire for Syria must be applied across the country, including in Afrin.

Bozdag said earlier on Monday that the UN decision "did not affect the Afrin operation".