The Turkish army said it launched new strikes on Saturday against the Kurdish People's Protection Units (YPG) militia in northern Syria, amid mounting expectations of a cross-border ground operation.

The army said it hit in “legitimate self-defence” camps and refuges used by the YPG in response to fire coming from the Afrin region controlled by the militia group, which Turkey deems to be a terror organisation.

Similar strikes had also taken place on Friday, it confirmed.

President Recep Tayyip Erdogan has repeatedly threatened over the last days to launch a ground operation, also including pro-Ankara Syrian rebels, to oust the YPG from Afrin and the area.

Turkey accuses the YPG of being the Syrian offshoot of the Kurdistan Workers Party (PKK) which has waged a rebellion in the Turkish southeast for more than three decades and is regarded as a terror group by Ankara and its Western allies.

But the YPG has been the key ally of Turkey's fellow NATO member the United States (US) in the fight against Islamic State militants, playing a key role in pushing the extremists out of their Syrian strongholds.

Turkish Defence Minister Nurettin Canikli said on Friday that the operation had “de-facto begun” because of the shelling but confirmed that Turkish troops had not yet crossed over into Syria.

Analysts say that crucial for any major ground operation will be approval from Moscow which has a military presence in the area and a cordial relationship with the YPG.

Turkey's army chief General Hulusi Akar and spy chief Hakan Fidan were in Moscow on Thursday for talks with Russian counterparts on Syria.