Turkish media reports said on Tuesday that Turkish jets shot down a warplane that violated national airspace at the border with Syria.
Video footage of the incident showed a warplane crashing onto a hill and two crew members apparently parachuting safely.
The Dogan news agency, quoting unnamed military officials, said the plane crashed into Syrian territory close to the border with Turkey.
The agency did not say what nation the plane was from.
Russian news agencies were saying that the Defence Ministry said that a Russian jet had been downed over Turkey near Syrian border.
A Turkish government official could not confirm the report, but a statement from Prime Minister Ahmet Davutoglu's office said the Turkish leader spoke with Turkey's military chief and foreign ministry about the incident.
It said Davutoglu would start "initiatives" within NATO and the United Nations.
Rami Abdurrahman who heads the Britain-based Syrian Observatory for Human Rights said the warplane crashed in the Turkmen Mountains region in the coastal province of Latakia.
He said it is not yet clear if the warplane was Russian or Syrian. He added that the fate of the pilot and co-pilot was not known yet.
The Turkomen Mountains region has been subjected to a government offensive over the past days under the cover of Russian airstrikes.
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