London: The shooting down of a Russian fighter jet on the Turkey-Syria border is a grave development that could push the world back towards the darkest hour of the Cold War, a foreign policy expert has warned.
There are early signs that Russia will respond to the incident aggressively, rather than diplomatically, warned analyst Lukasz Kulesa.
Kulesa, London-based research director at the European Leadership Network, has been tracking rising tensions between NATO and Russia for the last two years.
His group observed a tripling of close encounters between the Russian and NATO militaries since the annexation of Crimea in 2014. NATO countries have repeatedly scrambled to intercept Russian bombers, fighter jets and tanker aircraft set on provocative flight paths close to NATO nations' airspace.
"Unfortunately this (shooting down of the Su-24) is not terribly surprising," Mr Kulesa said.
Turkey warned in October it would not tolerate any more Russian incursions into its airspace.
"This is a very sad confirmation of a problem that was there before."
The situation was still very dynamic, and a lot would depend on emerging evidence of the plane's precise flight path and location.
On Wednesday Reuters reported the United States believed the jet was shot down inside Syrian airspace after a brief incursion into Turkish airspace.
A US official, speaking on condition of anonymity, said the assessment was based on detection of the heat signature of the jet.
However "this is getting us back to the darkest hour of the Cold War with the Soviet Union", Mr Kulesa said. "The situation is very grave, it can develop to even more dangerous crisis than it already is."
The initial reaction from Russian president Vladimir Putin was "menacing", he said.
"Instead of trying to de-escalate tensions and trying to work to resolve them, he accused Turkey of helping terrorists, and almost of working with ISIS,
"This is a very dangerous approach to take. It can very easily escalate further, if they decide to retaliate."
Turkey could also escalate the situation, by invoking the NATO treaty and demanding military support from its allies, Mr Kulesa said.
"I am sure they want expressions of political support and solidarity, but the question is do they want to go further – would they ask for any operational support, for example early warning aircraft or ground-air missile defence to be deployed?"
On the other hand, Turkey may move to de-escalate tensions, believing it has sent enough of a message by shooting down the jet.
Turkey has control of the Bosporus Straits and Dardanelles, crucial for Russian naval access to support its Syrian operations, however, Mr Kulesa thought it unlikely Turkey would use this as leverage, as it had a long tradition of observing the Montreux Convention that grants free passage to naval ships from Black Sea states including Russia.
Russia could choose to punish Turkey without resorting to military force, Mr Kulesa said.
"Economic sanctions are one very obvious resort," he said. "There are also Russian investments in Turkey, this can be put on the table, and the downgrading of the diplomatic relationship – these are issues right now under consideration in Moscow."
The pride of both nations, versus their ability to defuse tensions by top-level contact, will determine whether this incident will have bigger consequences.
"This is the clash of two very strong personalities," Mr Kulesa said.
