KIEV — A separatist commander is gunned down while dining in a Moscow restaurant. Law enforcement agents uncover a makeshift underground pipeline pumping oil from Russia into a Ukrainian border village. Rebel leaders carry out a widespread purge in one of Ukraine’s breakaway regions, detaining senior officials and military personnel alike.

Seemingly disparate events, but is the black market the common link?

A key conduit for international contraband, Ukraine has a rich heritage of smuggling. Mafia syndicates have long operated in the country’s rough-and-ready, eastern Donbas region, and the turmoil of war there has done little to disrupt the interconnected underworlds of Russia and Ukraine. Rather, conflict has simply opened up a new front in economic opportunities for war profiteers, corrupt public officials and the criminal classes to exploit.

In late 2014, Kiev’s government imposed an economic blockade around the self-proclaimed Donetsk and Luhansk People’s Republics (DNR and LNR respectively). Seemingly endless lines of traffic now snake toward military checkpoints in the buffer zone as soldiers scour cars for prohibited goods and counter-smuggling mobile units patrol the porous front line.

The end result in the breakaway regions is inflated prices. shortages in food, fuel and medicine, and a boost to the black market. These problems are compounded by continued fighting, ruined economic infrastructure and the separatist authorities' financial mismanagement. Many civilians in rebel-controlled areas are forced to rely on aid handouts or sporadic contact with local smuggling rings.

The main prize in the industrial, war-wracked Donbas region is the illicit trade in Ukrainian coal and Russian oil. At the retail end, smuggled fuel is most often sold at car-repair garages and tire dealerships, with most operations run by low-level opportunists. Ukraine’s security services, the SBU, publicizes its anti-smuggling efforts with occasional photos of masked agents digging up illegal pipelines, which can run to a few miles in length.

Business arrangements among smugglers in government-controlled territory appear stable, but the situation among the Russian-backed separatists is highly volatile. Profits may be lucrative but the fight for them is vicious, and business disputes can turn bloody.

Take the case of Yevgeny Zhilin. During Kiev’s pro-European street protests in the winter of 2013-2014, this former fight club manager emerged as a key militant counterrevolutionary. He later raised a separatist battalion as the east descended into armed conflict. Last month, the 40-year-old was murdered in an exclusive restaurant on the outskirts of the Russian capital. It seems a business deal had soured. A source told the respected Kommersant newspaper that Zhilin was killed in a feud over the control of sales of gasoline, diesel and coal.

Around the same time, LNR erupted with factional infighting. Dozens of regime figures were imprisoned and a former prime minister, Gennady Tsypkalov, died in detention under mysterious circumstances. One insider described it as a “power struggle within the remnants of the Party of Regions,” referring to the dissolved political party of Viktor Yanukovych, Ukraine’s ousted president and notorious kleptocrat. Smuggling routes provide a key source of revenue for Ukraine’s separatist elite, and some of those detained in the purge reputedly presided over the unregulated trade in energy supplies. Wealth and power go hand in hand, and some regard the crackdown as a means of consolidating both.

At the height of this purge, separatist officials released dubious photos of a large weapons cache and claimed that would-be assassins were planning to kill LNR’s leader, Igor Plotnitsky (who had already survived an attempt on his life this summer). The purported haul provided a fine pretext to clamp down on internal opponents and allegedly included numerous assault rifles, 30 grenades, 1.5 kilograms of plastic explosives, 138 boxes of ammunition and a hand-held flamethrower.

While the sheer size of this arsenal raised eyebrows, it was a reminder of one of the most time-honored traditions of the Ukrainian underworld: gun-running.

This post-Soviet nation is one of the world’s largest arms manufacturers and has long been a major gateway for illegal weapons shipments, centering historically on the extravagantly corrupt Black Sea port of Odessa. The combination of armed conflict and the prevalence of irregular, uncontrolled militias has increased the risk of an illicit arms market spiraling out of control. So far, however, continued hostilities act as a magnet for weapons; high demand keeps them concentrated around the front line.

The big concern is what happens to these guns, bombs and bullets once the war ends.