One of the world's most volatile regions was roiled further Tuesday when a Russian warplane went down near the Turkish-Syria border. Turkey said it "responded" to a plane after the aircraft repeatedly violated its airspace and ignored several warnings.
Turkey's semi-official Anadolu news agency quoted Turkish presidential sources in reporting that the Russian Su-24 was "hit within the framework of engagement rules" in Syria's Bayirbucak area, near the border with Turkey.
But Russia's state-run Sputnik news agency said that, "According to preliminary reports, the plane was gunned down from the ground."
Russian officials denied that the plane had violated Turkish airspace. Both pilots ejected from the plane, but their fate is unknown, Sputnik said.
Turkey released a purported image of the flight path of the Russian plane showing that it had violated Turkish airspace, but the Russian Defense Ministry said "objective monitoring confirmed" the plane was not in Turkish airspace.
"The Su-24 bomber jet was in Syrian airspace at the altitude 6,000 meters, the Russian Defense Ministry said," according to Sputnik. "The pilots were reportedly able to parachute out of the jet before it crashed."
Syria has been embroiled for four and a half years in a brutal civil war that has killed hundreds thousands of people, sent millions fleeing, and laid waste to entire cities.
Turkey vehemently opposes the Syrian regime of Bashar al-Assad. Russia is propping up the Assad regime.
Skirmishes between Turks and Syrians have taken place in the past, with Turkish officials accusing Syrian planes of violating Turkish air space.
A 'significant escalation'
"The moment of the plane falling into Bayirbucak region across from Hatay's Yayladagi was captured on camera," the Anadolu Agency reported. "The pilot's evacuation via parachute was also captured. Heavy smoke has been seen in the area where the plane fell."
This kind of incident might ultimately have been inevitable, given the number of countries involved either directly or indirectly in the Syrian war. Currently, the United States, Russia, France, the Gulf states, Turkey and Israel are involved in one way or another in military activity in Syria.
Sajjan Gohel, international security director for the Asia-Pacific Foundation, a think tank, described the downing of the plane as "a very significant escalation."
"It's very much the last thing that's needed right now, especially in the aftermath of the Paris attacks, when there was hope that Russia could form an alliance with France and with the United States against ISIS," Gohel said. "This is going to complicate things. This is going to add unnecessary tensions that really weren't required at this critical juncture."
He said the downing of the Russian plane would hamper efforts to form a united front against the terrorist group ISIS.
"This is a situation that unfortunately was almost inevitable at some point, because Turkey has long been accusing Russia of interfering in their airspace," Gohel said. "They've threatened them in the past. And even though economic relations between the two countries are strong -- politically, there have been tensions recently."
NATO 'in contact with Turkish authorities'
Turkey is a member of the NATO military alliance, which views an attack on one member as an attack on all. A NATO officials told CNN on Tuesday that the alliance was monitoring the events closely.
#BREAKING Flight radar track on downed warplane issued by Turkish military
The official would not comment on suggestions the NATO council -- which is in a scheduled session today to discuss other matters - would also discuss today's incident, but did say: "when Russian jets violated Turkish airspace a few weeks the council did meet in an extraordinary session, which resulted in a condemnation of the incursion."
The official would not comment on whether the Alliance was in contact with Russian authorities over the incident.
Syria's internal conflict has become a massive proxy war for numerous international powers, both in the region and outside it -- a situation that has added to the perception that incidents such as Tuesday were inevitable.
Currently, the US, Russia, France, the Gulf states, Turkey, Israel, Iran, Jordan and the Hezbollah are involved in one way or another in military activity in Syria.
"Russia has a slight get-out-of-jail-for-free card, in that it hasn't lost any actual lives here, but it is insisting that its plane didn't crossed into Turkish airspace," said CNN's Nick Paton Walsh
"They have tried in the past to have meetings in Ankara and Istanbul between Turkish and Russian officials to make sure misunderstandings didn't happen, and it's clearly failed.," Walsh said.
This incident has the potential to be extraordinarily damaging, but Russia is unlikely to want to start a major conflict with Turkey, a NATO member, over an incident like this that could technically be blamed on this jet straying according to the Turkish into the wrong territory, Walsh said.
Turkey shot down Syrian fighter previously
In March of 2014, Turkey shot down a Syrian fighter jet after the warplane strayed into its airspace, according to then-Prime Minister Recep Tayyip Erdogan. Erdogan is now the country's president
"Our F-16s went up in the air and shot that plane down. Why? Because if you violate my airspace, then from now on, our slap will be hard," Erdogan told supporters at a campaign rally in 2014.
But state-run media in Syria called it an act of "blatant aggression" and said the downed plane was over northern Syria at the time.