A wall of snow-capped mountains is all that divides Armenia and Azerbaijan. The neighbouring former Soviet Republics fought a brutal war just two years ago and now, if the worst fears are to be believed, could be on the verge on an all-out conflict once again.

Just past the mountainside city of Goris lies the Lachin Corridor, the only road in or out of the disputed region of Nagorno-Karabakh. Inside Azerbaijan’s internationally-recognised borders, it has been held by its ethnic Armenian majority since a war that followed the fall of the Soviet Union, with around a million ethnic Azerbaijanis pushed out and the separatists taking control of around 4,000 square kilometers of territory.

Now though, the 100,000 people who call it home are cut off from the outside world. In the three decades since the first Karabakh War, Azerbaijan has transformed from a run-down colonial backwater to an immensely wealthy, modern state, thanks to both its massive oil and gas reserves and its close ties with Turkey. In 2020, its well-trained, well-equipped armed forces rolled across the mine-strewn fortified frontier into Nagorno-Karabakh, taking back an area of land the size of Lebanon after a series of fierce battles and preparing to resettle some of those who were displaced thirty years before.

Only a Moscow-brokered peace deal put an end to the fighting, leaving the Karabakh Armenians in control of their de facto capital, Stepanakert, and a number of towns and villages around it. Russian peacekeepers were deployed to hold the line and prevent further bloodshed, but distracted by its increasingly catastrophic war in Ukraine, Moscow is looking less and less able to enforce the status quo.

On Monday, a group of Azerbaijanis describing themselves as environmental activists pushed past the Russians and blocked the Lachin Corridor in a row ostensibly over the extraction of natural resources in Armenian-controlled Karabakh. The demonstrators, none of whom appear to have a particularly long record of environmentalism or public protest, were accompanied by television crews, erecting tents and making it clear they were there for the long haul.

The sole route in or out of Nagorno-Karabakh has now been blocked for more than 24 hours, leaving motorists travelling from Armenia to the disputed region stranded in their cars in freezing temperatures and holding up shipments of essential goods. “This is part of Azerbaijan’s genocidal policy,” Davit Babayan, the unrecognized Nagorno-Karabakh Republic’s Foreign Minister announced at a crisis press conference in Stepanakert.

The supply of gas to the region has also since reportedly been cut, leaving locals without heating as temperatures are predicted to fall below freezing.

The blockade is the longest-running since the 2020 war, but the second in recent weeks. At the start of December, Azerbaijani officials moved to block the Lachin Corridor in an effort to inspect vehicles they say are transporting ‘stolen’ gold from mines in Armenian-held Karabakh, which they consider to be looting of their country’s natural resources. A tense standoff with the Russian peacekeepers ensued, and the flow of traffic was restored after a few hours.

As well as accusing the Armenians of using the Lachin Corridor to illegally export resources, Baku say it is also being used to ferry in military hardware and foreign nationals – including 14 Iranian citizens. Officials in Stepanakert deny the claims, and Armenian Prime Minister Nikol Pashinyan has said the allegations are an attempt “to create grounds, invented grounds, for closing the Lachin Corridor, surrounding the Nagorno-Karabakh Armenians, and subjecting them to genocide and expatriation, under the pretext of Armenia not fulfilling its obligations.”

Azerbaijani President Ilham Aliyev has also tied the status of the Lachin Corridor to his demand that Armenia give up a 35-kilometre stretch of land along its southern border with Iran for use as a ‘sovereign highway’ between the mainland of his country and its exclave, Nakhichevan. According to him, the so-called Zangezur Corridor was a condition of the 2020 ceasefire, while the Armenians argue they are only obliged to open their borders for traffic from Azerbaijan, not hand over part of their own territory. “For two years, we have not been interfering with the cars moving from Armenia to Karabakh and in the opposite direction along the Lachin road,” Aliyev said in November. “How much longer are we supposed to wait?”

Now, with the row reaching crisis point, there are fears of a signficiant escalation. “If Azerbaijan keeps the road closed, we will have a humanitarian catastrophe,” says Tigran Grigoryan, an Armenian political analyst and former opposition politician from Stepanakert. Tom de Waal, a senior fellow at Carnegie Europe and author of several books about the conflict, has claimed that the environmental protestors are akin to the “Little Green Men” used by Russia to occupy Crimea in 2014 while denying it was invading. With the two sides failing to find diplomatic common ground, “there’s a big risk that we get a serious new outbreak of violence by default,” he tweeted.

Given a major Azerbaijani offensive in August saw hundreds of servicemen killed and Armenian society gear up for what could be an existential war, collecting supplies for soldiers and laying on paramilitary training for civilians, everyone is on edge. For the time being, many of those who call Nagorno-Karabakh home are stuck, on one side of the mountains or the other.