Russian President Vladimir Putin on Thursday vowed Turkey's leadership would be made to regret the downing of one of Moscow's warplanes as the top diplomats from both countries held their first high-level meeting since the incident.
Moscow announced a halt to talks on a major gas pipeline with NATO member Ankara as Putin fired another salvo in their war of words, while Turkish leader Recep Tayyip Erdogan shot back by claiming he had "proof" Russia was involved in illegal oil trading with the Islamic State group.
Turkey has become Moscow's prime international sparring partner after it shot down a Russian jet on its border with Syria on November 24 -- sparking fury and economic sanctions from the Kremlin.
Erdogan's claims of Russian complicity with IS mirror allegations made by Moscow against Turkey and its leader in recent days.
"We will not forget this complicity with terrorists. We always considered and will always consider treachery to be the ultimate and lowest act. Let those in Turkey who shot our pilots in the back know this," Putin told lawmakers in his annual state of the nation speech, which also focused on Russia's air strikes in Syria.
Russia has accused Erdogan and his family of personally profiting from the oil trade with IS, which controls a large chunk of Syrian territory including many oil fields.
"We know for example who in Turkey fills their pockets and allows terrorists to make money from the stolen oil in Syria," Putin said.
"It is precisely with this money that the bandits recruit mercenaries, buy arms and organise inhuman terrorist acts aimed against our citizens, the citizens of France, Lebanon, Mali and other countries."
Erdogan has furiously denied the accusations against him and his family and said Turkey had proof that Russia was, in fact, involved in trading oil with IS.
"We have the proof in our hands. We will reveal it to the world," the Turkish leader said in a televised speech in Ankara.
Putin, whose administration has already announced sanctions against Ankara including a ban on the import of some Turkish foods, and reintroduced visas for visitors from the country, insisted Turkey would be made to regret its actions.
"We will not rattle our sabres. But if someone thinks that after committing heinous war crimes, the murder of our people, it will end with (an embargo on) tomatoes and limitations in construction and other fields then they are deeply mistaken," Putin said.
"We will not stop reminding them of what they did and they will not stop regretting their actions."
Immediately after the speech Russia's energy minister Alexander Novak announced the suspension of talks between Ankara and Moscow over the major TurkStream pipeline project.
Negotiations over the project to pipe Russian gas to Turkey under the Black Sea have been floundering since Moscow launched air strikes in Syria in late September in support of the regime of President Bashar al-Assad, which Ankara fiercely opposes.
But the official announcement of the break-off in the talks dealt another blow to floundering Russian-Turkish ties, as Putin lamented the damage to a relationship that he has spent years nurturing.
"Only Allah, most likely, knows why they did this. And evidently Allah decided to punish the ruling clique in Turkey by depriving them of their intelligence and reason," he said.
The latest furious exchange comes as the two countries' top diplomats met for the first face-to-face meeting between the two sides since the plane incident.
Russian Foreign Minister Sergei Lavrov agreed to talks with his Turkish counterpart Mevlut Cavusoglu on the sidelines of a conference in Belgrade after Putin on Monday snubbed Erdogan at the UN climate summit in Paris.
There appears, however, little chance that the two sides will lower the tone as the two strongmen insist the other should apologise over the incident.
Turkish Prime Minister Ahmet Davutoglu on Thursday accused Moscow of running a "Soviet propaganda machine".
"There was a Soviet propaganda machine in the Cold War era," Davutoglu told reporters in Ankara.
"They were called Pravda lies," he said, referring to the daily newspaper that was the mouthpiece of the Communist Party.