Russian Defense Minister Sergey Shoygu said on his ministry's Twitter feed that the country would deploy S-400 defense missile systems to its Hmeymim air base near Latakia, on Syria's Mediterranean coast.
And Foreign Minister Sergey Lavrov told Russian TV on Wednesday that Russia has "serious doubts" that Turkey's downing of its warplane Tuesday was "an unpremeditated act."
"It looks very much like a planned provocation," Lavrov said.
Turkish President Recep Tayyip Erdogan condemned what he said was the violation of airspace by Russian warplanes, calling the incident an infringement of his country's sovereignty.
He charged Russia with propping up the Syrian regime of Bashar al-Assad -- a regime he said was inflicting terrorism on its own people. His remarks came a day after Russian President Vladimir Putin accused Turkey of being "the terrorists' accomplices" for shooting down a plane he claimed was on an anti-terrorism mission.
Erdogan disputed that claim in a speech.
"There is no Daesh" in the area where the Russian planes were flying, Erdogan said, using another name for ISIS. "Do not deceive us! We know the locations of Daesh."
An alarming wave of international turbulence
And experts agreed.
"None of the targets that ... the Russians were going after had anything to do with ISIS. Those were all those Turkmen groups," said CNN military analyst Cedric Leighton, a retired U.S. Air Force colonel.
The Turkmen minority in that part of northern Syria has strong ties to the Turkish government, which wants to afford them a degree of protection. Anyone who bombs that area attacks "our brothers and sisters -- Turkmen," Erdogan said.
Turkish Prime Minister Ahmet Davutoglu said his country doesn't want to "drive a wedge" into its relationship with Russia, according to the semiofficial Anadolu news agency. And the foreign ministers of these two nations have already spoken by phone and plan to meet in person over the coming days, the news agency also reported, citing Turkish Foreign Ministry spokesman Tanju Bilgic.
Russia's Foreign Affairs ministry said Lavrov "expressed indignation" over the incident in the phone call.
Two high-ranking Russian military officers have visited the Turkish general staff since the shootdown, Anadolu reported.
"Every question about the incident has been answered," the general staff said, according to Anadolu. It said that images from radar displays were shown to the Russian attaches during visits in Ankara.
Even as Erdogan has insisted Turkey doesn't want to escalate the situation, the anger in his words -- and those of Putin -- showed that the conflict in Syria has now churned up a new and alarming wave of international turbulence.
The stakes are high in Syria, where the United States, Russia and a swarm of other global, regional and local forces are entangled in the civil war.
Turkey releases tape
Turkey, a NATO member, said it had repeatedly warned the Russian warplane, shooting it down only after it ignored several warnings and violated Turkish airspace.
Russia rejected that version of events, with the rescued co-pilot Capt. Konstantin Murakhtin telling state media reporters that "there were no warnings -- not via the radio, not visually."
"If they wanted to warn us, they could have shown themselves by heading on a parallel course," Murakhtin said, according to the official Sputnik news agency. "But there was nothing."
Russian officials have also asserted that the Sukhoi Su-24 bomber was attacked 1 kilometer inside Syrian territory.
But Erdogan said parts of the downed plane had fallen inside Turkey, injuring two people.
On Wednesday, Turkey's military released an audio recording of what it says was its warning to the Russian warplane.
In one portion, a voice is heard saying: "This is Turkish Air Force speaking on guard. You are approaching Turkish airspace. Change your heading south immediately. Change your heading south."
Russia has not yet commented on the audio.
The plane's crew
Adding to the tensions were questions about the fates of the two Russian pilots aboard the bomber.
Turkmen rebels operating in the area of Syria where the plane went down appeared to claim in a video that they shot both pilots to death as they parachuted toward the ground.
The Russian military said it believed one of the pilots is dead. The Russian Defense Ministry said Wednesday that the second pilot had been rescued and was safe.
The military also said a Russian marine was killed when a helicopter came under attack during the search and rescue efforts.
The deaths are Russia's first acknowledged casualties since it waded into the bitter Syrian conflict less than two months ago.
They highlight the risks in Putin's decision to support Assad, coming less than a month after another player in the war, the terrorist group ISIS, claimed responsibility for the deadly bombing of a Russian passenger jet over Egypt.
'The importance of de-escalating the situation'
U.S. President Barack Obama spoke to Erdogan by phone Tuesday and "expressed U.S. and NATO support for Turkey's right to defend its sovereignty," the White House said.
"The leaders agreed on the importance of de-escalating the situation and pursuing arrangements to ensure that such incidents do not happen again," it said.
But removing all risk of clashes in the crowded Syrian battlefield appears tricky, with regional foes like Iran and Saudi Arabia involved. Syria's civil war has killed hundreds of thousands of people and forced millions to flee their homes and their country.
Expert: Putin is 'a bully' but also 'rational'
Lt. Gen. Sergei Rudskoy, a senior official in the General Staff of the Russian Armed Forces, said military-level contacts with Turkey would be terminated
-- hardly a move likely to help avoid future skirmishes.
Putin could also seek to hurt Turkey economically, analysts said.
"Turkey receives about 60% of its natural gas supplies from Russia," said Nicholas Burns, a former U.S. ambassador to NATO. "So there are things the Russians could do to make their displeasure felt."
In the near term, the clash appears likely to have derailed French President Francois Hollande's hopes of forming a broader coalition against ISIS -- including the United States, Russia and others -- in the aftermath of the terrorist attacks on Paris. Hollande is scheduled to visit Putin in Moscow on Thursday.