The tensions between Russia and Turkey show no sign of abating, with Anatoly Antonov, the Russian defense minister, repeating the allegation that Turkey trades oil with the Islamic State—and taking it one step further: accusing President Recep Tayyip Erdogan and his family of personally profiting from the business.

“Turkey is the main destination for the oil stolen from its legitimate owners, which are Syria and Iraq. Turkey resells this oil,” Antonov said at a Defense Ministry briefing in Moscow. “The appalling part about it is that the country’s top political leadership is involved in the illegal business—President Erdogan and his family.”

The briefing was dedicated to showcasing what Russia says is Turkey’s connection to the oil trade with the Islamic State, and it threatens to shred whatever hope was left for a rapprochement between the two countries. Tensions have been high ever since Russia began airstrikes in September in Syria, on behalf of President Bashar al-Assad, against the Islamic State and other groups, including some allied with Turkey and the West. They became heightened after Russian warplanes were accused of violating Turkish airspace, and reached a peak on November 24 when Turkey shot down a Russian warplane.

Russian President Vladimir Putin called the incident “a stab in the back, carried out by the accomplices of terrorists.” Then, in Paris this week, he increased the rhetoric: “We have every reason to believe that the decision to shoot down our aircraft was dictated by the desire to ensure the safety of supply routes of oil to Turkey, to the ports where they are shipped in tankers.”

Erdogan vehemently rejected the claim, calling it slanderous and saying he would resign as president if the allegation could be proven. Cut to Wednesday’s news conference in Moscow: Officials presented photographs of what they said were oil-delivery convoys at Syria’s border with Turkey.

Sergei Rudskoy, the head of the Russian General Staff’s operative command, said three main oil routes had been identified: The western route to Turkish ports in the Mediterranean; the northern to Patma oil refinery; the eastern to Cazri transfer point. The oil is then being delivered to third countries, he said.

Officials at the briefing said the Islamic State was earning $3 million a day from the trade, but that figure had been halved after the Russian airstrikes began.

Russia is Turkey’s third-biggest trading partner and the tensions are likely to have some impact on its fragile economy. Russia has announced several measures, including visa restrictions and economic steps, in retaliation for the downed plane.

Turkey denies it buys oil from the Islamic State, but several news reports suggest Turkey tolerates some level of oil smuggling from its southeastern borders with Iraq and Syria. (For an assessment of these claims, read this.) Assad, Putin’s ally in the Syrian civil war, has also been accused of buying oil from the Islamic State, a group that his forces are ostensibly fighting.