Turkey has shot down two Syrian warplanes over Idlib and struck a military airport well beyond its frontlines in a sharp escalation of its military operations following the death of dozens of Turkish soldiers last week.
Syrian TV released a video showing soldiers watching as the Syrian pilots used their parachutes to land in a field nearby. The broadcaster reported that the four pilots had landed safely.
Turkey, which backs opposition forces in Idlib, said it had also targeted Syrian air defence systems and dozens of tanks.
Ankara has ramped up its attacks, including drone strikes, against the Russian-backed Syrian forces since Thursday, when 33 Turkish soldiers were killed in an air strike by Damascus.
It has already deployed thousands of troops and military vehicles in northwest Syria's Idlib province in the last month to stem advances by Syrian Government forces which have displaced 1 million people close to Turkey's southern border.
Already hosting 3.6 million Syrian refugees, Ankara is determined to prevent any further influx from Syria.
It has also let migrants cross its borders into the European Union, in an apparent effort to press for EU support in tackling the Syria crisis.
'Operation Spring Shield'
'Operation Spring Shield' is Turkey's fourth incursion in Syria in four years. Photo: AP
Defence Minister Hulusi Akar said earlier on Sunday that in the last four days Turkish forces destroyed eight helicopters, 103 tanks, 72 howitzers, rocket launchers, a drone and six air defence systems.
Mr Akar said 2,212 Syrian fighters had been "neutralised".
He dubbed Turkey's operation, its fourth incursion in Syria in four years, "Operation Spring Shield".
In response, Syria's army said it shot down three Turkish drones and warned it would take down any aircraft breaching the air space over the northwest, which has been controlled for years by Syrian President Bashar al-Assad's main ally Russia.
Despite the warning, Turkey downed two Syrian warplanes on Sunday, while Turkey's state-owned Anadolu agency said the Turkish military had targeted and rendered Nayrab Airport unusable, west of Aleppo city.
Turkey-backed opposition commanders also said Kuweires Airport, east of Nayrab, had been bombed since midnight.
Both airports are well inside Syrian Government controlled territory, marking a significant expansion of Ankara's targets.
The fighting has risked drawing Russia and Turkey, who cooperated for years to contain the fighting despite backing rival sides in Syria's nine-year war, into direct conflict.
'Europe must take robust action'
Thousands of migrants and refugees massed at Turkey's western border on Sunday. Photo: AP
Thousands of migrants and refugees massed at Turkey's western frontier on Sunday, trying to enter Greece by land and sea after Turkey said its borders were open to those hoping to head to Europe.
A Turkish official said the fighting in Idlib was directly linked to Turkey's decision to open the gates for refugees to Europe.
He said Ankara had changed its focus to preparing for the possibility of new arrivals from Syria "instead of preventing refugees who intend to migrate to Europe".
"Europe and others must take robust action to address this monumental challenge," said Fahrettin Altun, the communications director for Turkey's President Recep Tayyip Erdogan.
"We can't be expected to do this on our own."
On the Greek-Turkish land border, Greek army and police patrols used tear gas and stun grenades to thwart attempts overnight by thousands to push into the country.
President Recep Tayyip Erdogan has frequently threatened to allow refugees into Europe unless more international support was provided. Photo: AP
Under a 6 billion euro ($10.24 billion) deal in 2016, Turkey agreed to stem the tide of refugees to Europe in return for financial aid, after more than a million people entered Europe in 2015.
It has since accused the EU of failing to honour the agreement, and Mr Erdogan has frequently threatened to allow refugees into Europe unless more international support was provided.
Turkey already hosts 3.6 million Syrian refugees, as well as many others from Africa, Asia and the Middle East.
The country shares a frontier with Greece and Bulgaria, both European Union members.