The frozen conflicts left behind by the soviet collapse have a dangerous tendency to heat up suddenly. nagorno-karabakh, the armenian-run enclave within azerbaijan where fighting has killed dozens since sunday, today risks sparking a broader conflagration. russia has links with both ex-soviet republics and has helped to defuse past escalations, but is part of a defence pact with armenia. turkeys president recep tayyip erdogan, meanwhile, has become a vocal supporter of azerbaijan. that puts the two regional powers potentially on opposite sides in a volatile region crossed by strategic oil and gas pipelines.

Mountainous nagorno-karabakh was an autonomous region in soviet azerbaijan until the late 1980s when the majority armenian local population accused baku of conducting forced azerification and sought to unite with armenia. war between the republics ensued, killing about 20,000 before a 1994 ceasefire froze the fighting without securing a long-term settlement. the so-called minsk group, co-chaired by france, russia and the us, has since mediated talks.

Unlike in several other post-soviet conflict zones, russia is not seeking to change borders and has no troops on the ground. indeed, moscow has little interest in a destabilising conflict in the southern caucasus and has sought to remain neutral in a dispute between moscow allies. but russia has a military base in armenia, and a defence agreement that contains a mutual assistance clause if the latter is attacked by a third country, though this does not cover nagorno-karabakh.

What has changed the dynamics is the role being played by mr erdogan and his growing appetite for military adventurism. turkey has close linguistic, ethnic, cultural and economic links with neighbouring azerbaijan. the extent of any material support is unclear. ankara has denied armenian claims that turkish-backed syrian mercenaries have been fighting in nagorno-karabakh. but turkish media have reported that azerbaijan used drones from a defence company run by a relative of mr erdogan.

While ankara has in the past insisted the conflict must be resolved peacefully, mr erdogan this time has altered the geopolitical balance by backing baku. he insisted the region would only be able to embrace peace and tranquility if armenia immediately withdraws from the azeri lands that it is occupying. in a stark illustration of the risks, armenia on tuesday said a turkish f-16 fighter had shot down one of its warplanes in armenian airspace, killing the pilot. turkey and azerbaijan denied the accusation.

Russia and turkeys strongmen have fallen out dangerously before, when turkey shot down a russian jet near the turkey-syria border in 2015, but they eventually made up. mr erdogan went ahead with buying russian air defence missiles, angering his nato allies. but nagorno-karabakh adds a third flashpoint, with ankara and moscow already supporting opposite sides in syrias and libyas civil wars. mr erdogan, suffering from a weak economy and in danger of overreaching, would be well-advised to temper his support for baku and join moscow instead in trying to restore calm.

Western countries have an important role, too. washington and paris, the minsk group co-chairs, were slow to respond to violence in july that foreshadowed the latest clashes. nato should impress upon mr erdogan the need for restraint, and make clear it will not come to his aid in any clash he is seen to have provoked. unless tensions cool, this particular frozen conflict could get very hot indeed.