Turkey's air force on Sunday downed an unidentified drone on the Syrian border after it breached Turkish air space six times, the defence ministry said.

“An unmanned aerial vehicle which violated our air space six times (on Saturday)... was downed by two of our F-16s which took off from Incirlik” air base in southern Turkey, the defence ministry said, sharing pictures of the downed drone.

The ministry said it was not known who the drone belonged to but said it was grounded at 1:24pm local time.

“The wreck of the drone was found at the Cildiroba base” by the Turkish gendarmerie in the Kilis province near the Syrian border, the ministry said.

The Turkish air force shot down a Russian Su-24, aircraft, in the Turkey-Syria border area in 2015, sparking an unprecedented crisis in the two countries' relations.

That was condemned by Russian President Vladimir Putin as a “stab in the back” but the two countries later reconciled and worked together on the Syrian crisis although they remain on opposite sides of the conflict.

Turkey backs rebels seeking the ouster of President Bashar al-Assad while Moscow is one of the few remaining allies of the regime in Damascus.

Safe zone

The Turkish military conducted two offensives in northern Syria against IS and Kurdish militia forces in 2016 and 2018.

The two NATO allies, Turkey and the United States, reached a deal last month to establish a safe zone between the Turkish border and Syrian areas east of the Euphrates river controlled by the Syrian Kurdish People's Protection Units (YPG).

The United States views the YPG as a close ally in the fight against the militant Islamic State (IS) group.

But Ankara says the YPG is a terrorist militia linked to the outlawed Kurdistan Workers' Party (PKK), which has waged an insurgency inside Turkey since 1984.

The PKK is blacklisted as a terrorist group by Ankara, the US and the European Union.

Turkish President Recep Tayyip Erdogan has repeatedly threatened to launch a cross-border offensive against the YPG if the plans to realise a safe zone with Washington fail by the end of this month.

Erdogan planned to meet with US President Donald Trump on the margins of the annual UN General Assembly meeting in New York but a bilateral meeting did not take place. The Turkish leader only attended a reception given by Trump for the heads of state.

Turkey's top national security council bringing together civilian and military leaders was due to meet on Monday under Erdogan's leadership, with the Syria issue expected to figure high on the agenda.

Erdogan has said up to three million Syrian refugees could be returned to a “safe zone” it is seeking to establish in northern Syria.

The country is already playing home to more than 3.6 million Syrian refugees — the highest number in the world — and there have been signs of a public backlash over their presence after eight long years of war in its neighbour to the south.

Analysts however say the scheme for a safe zone planned to be 30 kilometres deep and run 480 kilometres (300 miles) along the north of Syria is unrealistic as Washington is struggling to balance its ties with Ankara and the Kurdish militia.