Russian President Vladimir Putin on Thursday vowed that the Turkish leadership would be made to regret the downing of one of Moscow's warplanes, as Ankara presented its condolences for the death of a Russian pilot in 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 and Turkish leader Recep Tayyip Erdogan shot back by claiming he had "proof" Russia was involved in illegal oil trading with the Islamic State group.
Following talks with Russian Foreign Minister Sergei Lavrov in Belgrade in the highest bilateral level contact since the crisis began, Turkish Foreign Minister Mevlut Cavusoglu presented his condolences for the death of a Russian pilot in the incident.
But he stopped short of issuing the apology that Moscow has demanded and admitted that there had been no breakthrough in the 40-minute talks on the sidelines of a security conference.
Russia and Turkey have been plunged into their worst crisis since the Cold War over Turkey's downing of a Russian jet on its border with Syria on November 24 -- sparking fury and economic sanctions from the Kremlin.
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 will not forget this complicity with terrorists. We always considered and will always consider treachery to be the ultimate and lowest act," Putin told lawmakers in his annual state of the nation speech.
"We know for example who in Turkey fills their pockets and allows terrorists to make money from the stolen oil in Syria."
- 'Regret their actions' -
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.
Prime Minister Ahmet Davutoglu accused Moscow of running a "Soviet propaganda machine" along the lines of the Communist Party mouthpiece daily Pravda.
Putin, whose administration has already announced sanctions against Ankara including a ban on the import of some Turkish foods, and reintroduced visas for Turkish visitors, insisted Turkey would be made to regret its actions.
Signup to our newsletter and follow us on Facebook and Twitter!
"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."
Both Russian pilots ejected from the Su-24 plane after being shot down by two Turkish F-16s.
One was killed while parachuting to the ground -- in circumstances yet to be fully explained -- while a second was rescued by Russian and Syrian forces from the Syrian side of the border. Another Russian serviceman was killed in the rescue operation.
"We expressed our sadness and expressed our condolences for the Russian pilot who lost his life," Cavusoglu said after meeting Lavrov in the Serbian capital.
But he added: "It would not be realistic to say that the problems have been overcome in a first meeting."
The meeting was the first such high-level encounter since the shooting down, after Putin on Monday snubbed Erdogan at the UN climate summit in Paris.
In comments broadcast on Russian television, Lavrov also confirmed that there had been no breakthrough.
"We did not hear anything new. The Turkish minister confirmed the positions which they have already voiced," he said.
- 'Allah punished the elite' -
Immediately after Putin's 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 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.