Friction between Russia and Turkey, on display at a Russian press conference this week, is drawing attention to ISIS’s murky oil-selling operation. Photograph by Vadim Savitsky / Russian Defense Ministry Press Service via AP

On Wednesday, at a press conference in Moscow, Russia’s defense ministry presented several grainy photographs and fleeting video clips taken from the sky and from space. They showed large numbers of cars and trucks: in bizarre formations in the sands of eastern Syria, in neat columns along desert roads, clustered at official crossing points along the Turkish-Syrian border, and parked in orderly rows near port cities on Turkey’s Mediterranean coast. Some of these scenes are hundreds of miles apart. Anatoly Antonov, one of Russia’s nine deputy defense ministers, said that the images constitute “hard evidence” that there is “a single team acting in the region, composed of criminals and Turkish elites,” who are buying oil from ISIS “on an industrial scale.”

In the week since Turkey shot down a Russian jet over an alleged border violation, the rhetoric between the countries has grown increasingly barbed. Turkish President Recep Tayyip Erdoğan accused the Russians of “killing our Turkmen kinsmen hand-in-hand with the [Syrian] regime,” and promised that if another Russian jet crossed into Turkish airspace, “Turkey will be obliged to retaliate.” Meanwhile, at the climate talks in Paris, Russian President Vladimir Putin announced, “We have every reason to think that the decision to shoot down our plane was dictated by the desire to protect the oil-supply lines to Turkish territory,” specifically, those funding ISIS.

At the briefing in Moscow, Antonov went a step further. “This illegal business involves the country’s senior political leadership, including President Erdoğan and his family members,” he said. “Maybe I'm being too blunt, but one can only entrust control over this thieving business to one's closest associates.” Then he fawned over the journalists in the room, urging the “brave, courageous people in the press community, who do their job with integrity,” to continue his investigation, and emphasized, as if unravelling a conspiracy, that Erdogan’s son-in-law had recently been appointed minister of energy and natural resources. “Of course, the dirty oil money will work,” he added. “And I am pretty sure we are about to see a lot of speculation in the press maintaining that what you’ve seen today is fake evidence. Well, if that is so, let the journalists visit those areas, which are shown during the briefing.”

In fact, one of Russia’s satellite photographs showed a very familiar place. I first walked through the Bab al-Salama border crossing in April, 2013, and lived within sight of it for the next two summers. Then, too, trucks often lined the road leading down to the border gates, many of them parked for hours while drivers napped in an olive grove nearby, waiting for inspectors to finish checking the vehicles ahead of them. On the Turkish side, fourteen thousand Syrian refugees lived in a container camp nestled against the border. Beyond the Syrian gates, a comparable number of civilians lived at a transit camp under wretched conditions. A system of hoses transported clean drinking water from Turkey into huge tanks at the Syrian camp, but there was no way to dispose of waste, and it gathered in puddles next to the road and ruts in the mud. Both camps sprang up from nothing, out of necessity, as people from Aleppo and the villages to its north tried to escape the war. (Fleeing didn’t always help; in June, 2013, a Syrian jet strafed the transit camp, killing seven refugees.) Both camps are plainly visible in the Russian satellite pictures.

In those camps alone, tens of thousands of people depended on trucks delivering food and medical supplies. But most trucks going into Syria bypassed the camps, instead carrying goods to substantially more desperate and dangerous parts of the country. Parts of Aleppo were starving. Snipers targeted breadlines, and bakeries and markets in rebel-held territory were hit with bombs from above. In April, 2013, on the Syrian side of the border gates, I saw a flatbed truck with a black flag often used by Al Qaeda affixed below the windshield. It passed through, laden with large, white bags, seemingly filled with grains. A local rebel told me that Jabhat al-Nusra had begun transporting food to suffering neighborhoods in Aleppo, which, along with electricity, busing, and other infrastructure projects, resulted in a surge in popular support. Still, trucks under the control of militant groups were the exception, and the declaration of ISIS’s “caliphate,” a hundred and fifty miles southeast of Bab al-Salama, was more than a year away.

The practice of smuggling at the Turkish-Syrian border is decades older than the war. Aleppo once belonged to the Ottoman Empire; when it was cut off from Turkey, in 1924, after the Treaty of Lausanne established most of the modern border, locals continued transporting all manner of goods from the cheaper side to the more expensive side. Last year in Kilis, the closest Turkish town to the Bab al-Salama crossing, a box of cigarettes smuggled in from Syria would sell on the street for as little as fifty cents.

Syria’s most potent oilfields are in the Deir Ezzor province, largely under ISIS control. The group earns most of its money by taxing locals and confiscating valuables at checkpoints, but oil sales still account for hundreds of millions of dollars of revenue. Last week, the U.S. Treasury Department announced sanctions against George Haswani, a Syrian businessman who allegedly acted as a middleman for sales between ISIS and the beleaguered Assad regime. Hours after Antonov’s announcement in Moscow, the U.S. rejected the Russian claim against Erdoğan. “We frankly see no evidence, none, to support such an accusation,” a spokesman for the State Department told journalists. Instead, he said, ISIS sells oil to middlemen who transport it beyond the group’s territory, including into Turkey, through established smuggling routes.

Last year, the journalist Mike Giglio published a lengthy investigation, on BuzzFeed, into oil smuggling at the Turkish-Syrian border. He travelled to Besaslan, a Turkish village near an official crossing point, and found that much of the oil coming through this smuggling post originated in ISIS territory, many miles away. It was transported by middlemen to a nearby area in northwest Syria. In Besaslan, traders received the oil through a network of buried pipes, while spotters looked out for police. They filled drums and sold them to local Turkish businessmen, who, in turn, cut secret deals with gas stations or set up illegal filling stops. Soon after Giglio’s article was published, more than a thousand members of the Turkish security forces reportedly descended on Besaslan, arresting thirty-seven Syrians and Turks and destroying about eight miles of illegal pipes.

However enthusiastic the raid in Besaslan, numerous reports indicate that the Turkish government maintains murky alliances with a number of Islamist rebel groups in Syria. In January, 2014, three trucks escorted by the intelligence services were found to be transporting huge quantities of ammunition to a camp frequented by rebels with connections to Al Qaeda, according to an arrest order for one of the drivers. The Turkish newspaper Cumhuriyet published a video of the trucks, and last week its editor-in-chief was arrested on charges of collecting and revealing secret documents. Erdoğan insisted the trucks were carrying “humanitarian aid” for Turkmen in Syria, and personally accused the Cumhuriyet editor of “attempting to overthrow the government” of Turkey.