A local conflict over a remote region is in grave danger of turning into a new "regional war" that could suck in three major military powers – all with reasons to distrust one other.
All three either possess, store or are developing nuclear weapons and all have a formidable arsenal even if you take the nukes out of the equation.
There are fears of an "internationalisation of a conflict" that is as emotive as it is intractable.
Turkey, Russia and Iran are now all involved, to some degree, in the fighting between Armenia and Azerbaijan that burst into bloody life two weeks ago.
Hundreds have died in the disputed Nagorno-Karabakh region and thousands have fled to avoid the fighting. The BBC said on Sunday said the damage in the region was at a "massive scale".
Angry talk of "executioners", "driving away dogs", and a potential "genocide" fills local airwaves.
On Saturday, Armenia and Azerbaijan agreed to a ceasefire. However, given the bellicose language from both sides and the polar opposite positions of the two countries, the risk of battle resuming is high.
Iran, which borders both Armenia and Azerbaijan, has been doing its best to sit the skirmish out. It has said it wants peace. But it has now said shells have fallen on its border regions – and it won't stand for it.
"We must be attentive that the war between Armenia and Azerbaijan does not become a regional war," Iranian President Hassan Rouhani told the country's Cabinet on Wednesday.
"Iran will not allow anyone, on some pretext, to bring terrorists that Iran has fought for years to our border."
What terrorists? Well, President Rouhani didn't elaborate but it is thought to refer to Turkish-backed Syrian mercenaries, potentially former jihadists, that it's alleged are fighting alongside Azeri troops.
It's the clearest signal yet that the dispute is in danger of going wider. But Iran may not act in the way many people might assume.
INTRACTABLE CONFLICT BOILING OVER
At the heart of this growing conflict is the region of Nagorno-Karabakh, situated within central Asia's Caucasus mountains between the Caspian and Black seas.
Historically both Christian Armenians and Muslim Turks from Azerbaijan have called it home.
Officially Nagorno-Karabakh is part of Azerbaijan. However, since a war in the 1990s that killed 30,000, most of the area has been populated and governed by ethnic Armenians who call it the Republic of Artsakh.
Not a single nation recognises Artsakh – not even Armenia – but it is supported by the Armenian government in Yerevan.
For decades, there had been an uneasy truce. Then, late last month, war broke out as old animosities resurfaced.
Around 75,000 people have fled Nagorno-Karabakh, half the population, with Armenia accusing Azerbaijan of shelling the region's largest city of Stepanakert. It says a historic cathedral has also been hit.
The Azeri city of Tartar, close to Nagorno-Karabakh and normally home to 100,000 people, is now said to be a "ghost town" as residents leave. Azerbaijan has accused Armenia of shelling its second-largest city of Ganja.
"DRIVING AWAY DOGS"
Armenian Prime Minister Nikol Pashinyan told the BBC on Wednesday that if Azerbaijan succeeds, "it will mean a genocide for the Armenians of Nagorno-Karabakh".
That evokes memories of the 1914 genocide that saw the forerunner to modern Turkey accused of killing more than a million Armenians.
Azerbaijan President Ilham Aliyev, in turn, gave a fiery speech earlier this month where he talked of "liberating" Nagorno-Karabakh after decades of failed negotiations.
"For almost 30 years, Armenian executioners have occupied our lands, destroyed all our historical, religious and cultural sites."
"Now," He continued, "we are driving [Armenians] away like dogs."
Several analysts have said that Azerbaijan currently appears to have the "upper hand" in the conflict.
And that's because of the actions of Turkey.
Ankara denies it, but France has accused Turkey of being heavily involved supplying weapons and manpower to Azerbaijan, reported Aljazeera.
"The new aspect is that there is military involvement by Turkey which risks fuelling the internationalisation of the conflict," French foreign minister Jean-Yves Le Drian told the French Parliament.
RUSSIA'S HUGE BLOW
Russia will not be happy at Turkey's intervention into an area that was once part of the USSR. More than that, the two are on opposing sides of the Libya conflict and memories are still fresh in Moscow of the shooting down of a Russian jet by Turkish forces over Syria in 2015.
Of the two warring nations, Moscow is closer to Armenia, with which it has signed a mutual defence pact.
However, in a what would have been a huge blow to Armenia, Russian President Vladimir Putin said on Wednesday it would not be supporting Armenia while the fighting remained within the confines of Nagorno-Karabakh.
"It is deeply regrettable that the hostilities continue, but they are not taking place on Armenian territory," he said.
IRAN'S UNEXPECTED DECISION
Writing for think tank the Australian Strategic Policy Institute, international relations expert Mohammed Ayoob said there was the "alarming" prospect of the conflict dragging in regional superpowers.
"Turkey has traditionally been a staunch supporter of Azerbaijan [while] Russia considers Armenia a strategic ally, but also considers Azerbaijan a strategic partner.
"Russia will therefore have a major problem on its hands if the conflict escalates," said Prof Ayoob.
More than 10 million Iranians are ethnic Azeri, more than in Azerbaijan itself. But the assumption that Tehran would naturally support Azerbaijan, a fellow Muslim nation, could be wide of the mark.
"Iran, despite its attempt to appear neutral, has long supported Armenia," said Prof Ayoob.
"Both Iran and Azerbaijan are Shia but Azerbaijan's irredentist claim after independence on the northern Iranian provinces of East and West Azerbaijan has more than neutralised their religious affinity.
"There are too many external fingers in this Caucasus pie and unless this fire is doused quickly it has the potential to turn into a major regional conflict."
Baku's close links to Israel haven't exactly won it friends in Tehran either, leading Iran to lean towards Christian Armenia.
There have been reports of military hardware bound for Armenia being trucked through the Iranian border crossing of Norduz, reported Aljazeera. Iran has denied the "baseless rumours" and said the trucks were simply full of car parts.
But Iran is nevertheless rattled, particularly by Turkey's role. Tehran and Ankara backed different sides in the Syrian civil war and it would prefer not to have Turkish mercenaries, with no love for Iran, anywhere near its frontier.
Iran's defence minister Amir Hatami said shelling of its border towns would not be tolerated. Its patience is wearing thin.
"If this issue continues, more measures will be taken. It is not acceptable for the citizens of Iran to be harmed even by mistake."
Ominously, Hatami did not say what those extra "measures" might be.
Russia is a nuclear power; Turkey has US bombs on its territory and Iran is widely thought to be close to a nuclear capability.
It is next to unthinkable that weapons of mass destruction could become part of even a regional war. However, all three have a mountain of other weapons at their disposal.
Turkey is almost certainly supplying some of those to Azerbaijan; Iran has hinted at taking an active role if its territory is shelled and Russia might be obligated to finally come to Armenia's aid if the war spreads.
The ceasefire allows some breathing space for a solution to be found.
But if a solution remains as elusive as it has for the past three decades, there is every chance an intractable conflict high in the mountains of the Caucuses could turn into a very messy war involving three heavily armed enemies.