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Turkish fighter jets shot down a Russian warplane near the Syrian border on Tuesday, the first time a NATO member's armed forces have downed a Russian or Soviet military aircraft since the 1950s, and an act Russian president Vladimir Putin said would have "significant consequences."
Speaking at a joint press conference with French President François Hollande on Tuesday afternoon, President Obama urged all sides to proceed with caution. "We are still getting the details of what happened," he said, adding that "Turkey like every country has a right to defend its country and its airspace."
Obama appeared to lay the blame for the incident at the feet of the Russians.
"If Russia were directing its operations towards ISIL, some of those mistakes… are less likely to occur," using an alternative acronym for the Islamic State. Before the press conference, White House officials told Reuters that the "Russian incursion into Turkish airspace lasted seconds."
The fate of the pilots of the Sukhoi Su-24 fighter-bomber, a two-seater twin-engine jet, is not clear.
Turkey said the aircraft had violated its airspace and was warned 10 times in the space of five minutes before it was shot down by F-16 fighter jets. The country has requested an extraordinary NATO meeting to inform members about the incident, which is taking place in Brussels.
At first Russia's account of the downing of the plane conflicted with Turkey's, with its military saying the Su-24 had apparently come under fire from the ground. It also said it could prove the plane never left Syrian airspace.
Later Russian President Vladimir Putin confirmed it had been shot down by Turkish F-16s, calling the act a "stab in the back carried out by accomplices of terrorists."
Related: Turkey Says Russia Violated Its Airspace and Is Escalating Syria's Crisis
In a very strongly-worded statement, Putin said the plane fell on Syrian territory four kilometers (2.5 miles) from Turkey.
"Neither our pilots nor our jet threatened the territory of Turkey. This is obvious," he said, speaking ahead of a visit by King Abdullah II of Jordan in Sochi. "We will analyze everything, and today's tragic event will have significant consequences, including for Russia-Turkish relations."
"Do they want to make NATO serve ISIS? I understand that every state has its own regional interests and we've always respected that, but we will never allow the kind of crime that happened to today to take place. And of course we hope that the international community will find the strength to come together and fight against the common evil."
Footage from private broadcaster Haberturk TV showed a warplane going down in flames in a woodland area, a long plume of smoke trailing behind it. The plane went down in an area known by Turks as "Turkmen Mountain" in northern Syria near the Turkish border, Haberturk said. Ethnic Turks living there have been fighting the Assad government and the Islamic State for the past few weeks, and have been targeted by Russian airstrikes in support of the regime's army.
Separate footage from Turkey's Anadolu Agency showed two pilots parachuting out of the jet before it crashed.
The 10th Division, a Turkmen rebel group closely affiliated with the Free Syrian Army, published a video on Tuesday afternoon showing what appeared to be the bloodied corpse of one of the Russian airmen. Meanwhile, the deputy commander of another Turkmen unit told Turkey's Dogan News Agency that both pilots had been shot and killed while they were parachuting to earth.
The badge seen on the man's right arm matches Russian Air Force insignia. "A Russian pilot," a voice is heard saying as a group of men gather around him, "God is great."
VICE News could not independently confirm the authenticity of the video. Turkish government official told Reuters the pilots were believed still to be alive and that Ankara was working to secure their release from Syrian rebels.
One pilot is reported to be in the hands of anti-Assad rebels from the Alwiya Al-'Ashar group, Brookings Doha analyst Charles Lister told The Guardian.
On Tuesday, another Syrian insurgent group, which is a recipient of US weapons, claimed its fighters had used an American-made anti-tank TOW missile to destroy a Russian helicopter that had been sent to look for the pilots.
The helicopter had been forced to make an emergency landing in a nearby government-held area in Syria's Latakia province on Tuesday, the Syrian Observatory for Human Rights said. A video purports to show the destruction of the helicopter on the ground with a TOW missile.
Russia's air contingent in Syria is estimated at four Su-30 interceptors and roughly 12 each of the older Su-24 and Su-25 fighter-bombers, plus some Su-34 bombers.
A Turkish government official said its military's rules of engagement had been made public in the past and other nations knew the consequences of any violation of airspace.
"In line with the military rules of engagement, the Turkish authorities repeatedly warned an unidentified aircraft that they were 15 km (9 mi) or less away from the border," the official said. "The aircraft didn't heed the warnings and proceeded to fly over Turkey. The Turkish Air Forces responded by downing the aircraft."
"This isn't an action against any specific country: Our F-16s took necessary steps to defend Turkey's sovereign territory."
Shortly after 4pm Turkish time (9am ET) it was reported Turkish President Recep Tayyip Erdogan had called an emergency security summit with his top generals, heads of intelligence, Prime Minister Ahmet Davutoglu and other senior ministers.
Turkey called this week for a United Nations Security Council meeting to discuss attacks on Turkmens in neighbouring Syria, and last week Ankara summoned the Russian ambassador to protest the bombing of their villages.
Ankara has traditionally expressed solidarity with Syrian Turkmens, who are Syrians of Turkish descent.
About a dozen Turkmen rebel militias operate in Syria's coastal Latakia province. Both Turkmen groups that may have been responsible for shooting the Russian pilot or pilots as they parachuted from the jet have fought alongside more moderate opposition groups, as well as Islamist units and Syrian al-Qaeda affiliate Jabhat al-Nusra.
The 10th Division has close links with a joint operations centre created by the US and its allies known in Turkish as Musterek Operasyon Merkezi, or MOM, which provides vetted commanders with money and weapons, according to Charles Lister, a visiting fellow at the Brookings Doha Center.
A number of Turkmen militias have been formed in Syria during the course of the conflict, many of which have received training from Turkish security forces, as well as continued backing from Ankara. Most are now united under the Syrian Turkmen Brigades banner, divisions of which operate elsewhere in the country against both government troops and the so-called Islamic State.
The Turkmen people, who are Turkish by both ethnicity and language, have lived in the region for around 1,000 years. They faced harsh repression at the hands of Syria's ruling Baath party. Fighting between Turkmen brigades and pro-government forces — including Syrian regulars and the Lebanese Shia militant group Hezbollah — has been going on for weeks in the area close to the Turkish border where the jet was brought down, and Russian aircraft have repeatedly bombed the rebels.
The strikes were a source of serious concern for Turkey, and its foreign ministry summoned Russian Ambassador Andrei Karlov to complain about what it described in a November 20 statement as "the bombardment of civilian Turkmen villages" close to its Yaylada? border crossing. Turkish Foreign Minister Feridun Sinirlio?lu said that the bombings could result in "serious consequences".
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