Russian President Vladimir Putin again raised the stakes Thursday in his country's conflict with Turkey, using a press conference to dare the Turkish Air Force to try flying in Syrian airspace now that Russia has deployed sophisticated anti-aircraft missiles in the region.

Relations between Russia and Turkey – and specifically between Mr. Putin and Turkish President Recep Tayyip Erdogan – have been hostile since a Nov. 24 incident that saw a Turkish fighter jet shoot down a Russian Su-24 warplane that Ankara says briefly entered its airspace. One of the two pilots was shot dead by Syrian rebels as he parachuted to the ground; the other survived and was rescued.

While both Russia and Turkey claim to be taking part in the fight to destroy the Islamic State, their other aims in Syria are at loggerheads. Ankara has aided any and all groups that share its goal of toppling President Bashar al-Assad. Moscow, meanwhile, intervened in the conflict this fall to keep Mr. al-Assad's regime from collapsing.

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"We think the actions of the Turkish leadership toward our plane that was shot down were not just unfriendly, it was a hostile action – an act of enmity," Mr. Putin told his annual year-end news conference in Moscow. "Did they really think we would flee after the incident? That we would remove all our forces?" he continued. "Russia is not a country that withdraws or shies away from the challenge. On the contrary, we increased our military presence, we increased the number of our aircraft, we increased our anti-aircraft missiles, etc. Before that, the Turkish Air Force was flying over Syria. Well, I invite them to try flying over Syria now, because they will get a very serious response."

Turkey appears to have already been avoiding Syrian airspace since the incident. Turkish media have reported that the country's warplanes have stopped taking part in a U.S.-led campaign of air strikes against IS out of concern that Russian or Syrian forces would try to shoot down a Turkish jet in retaliation for the downing of the Su-24. (Russian jets, unlike planes from the U.S.-led coalition, are flying over Syria at the invitation of the government.)

Mr. Putin made plain that he was personally offended by the way the Turkish government handled the Su-24 incident. He said that if it had been an accident, he would have expected a phone call from Turkish leadership explaining what had happened. Instead, he noted, Ankara called immediately for an emergency meeting of the NATO military alliance.

The Russian president's fury was such that he descended toward the obscene while discussing relations with Turkey. At one point, he speculated that Turkey may have shot down the Russian jet at the behest of the United States, perhaps in exchange for the United States turning a blind eye to a recent Turkish military deployment in northern Iraq. "Maybe someone in the Turkish leadership decided to lick the Americans in a particular place," Mr. Putin said to applause.

He also said relations with Turkey had been good right up until Nov. 24 and that "the Turkish leadership" even approached him during last month's G20 summit in Antalya with a "delicate" request that Mr. Putin said was outside the boundaries of international law. He did not specify what was asked but said Russia had been ready to help.

No longer. "It is very difficult to achieve understanding with the leadership of Turkey. Again they backstabbed us. So on the inter-state level, I see no prospect of Russian-Turkish relations improving. There is no chance."

Suat Kiniklioglu, a former MP in Mr. Erdogan's AKP party who is now a critic of the government, said he believes Mr. Erdogan "miscalculated" in ordering the shooting down of the Russian jet.

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"Had [Mr. Erdogan] known the consequences would be as dramatic as they are now, I don't think he would have gone for it," Mr. Kiniklioglu said in an interview in Ankara. "He thought he was really good buddies with Putin. He respects Putin a lot and likes the way he challenges the West and the international order. He now understands Putin didn't give a damn about all of that and he only cares about Russia's national interests."

Mr. Erdogan has himself favoured anti-Western rhetoric in recent years, Mr. Kiniklioglu said, but when Russia responded angrily to the downing of the Su-24, "he suddenly remembered he's a NATO member and he made a full U-turn."

Mr. Putin, who met Wednesday with U.S. Secretary of State John Kerry, said he was supportive of a draft United Nations resolution that Mr. Kerry was preparing. It calls for a peace process that includes a new Syrian constitution and – eventually – elections.

"We support the U.S. initiative on Syria, as well as the proposed UN resolution. I think after reading the resolution project, the Syrian government will be content as well," Mr. Putin said.

In the meantime, however, he said Russia would continue its war effort in support of Mr. al-Assad. "We will continue our air strikes as long as the Syrian army continues to fight."