The downing of a Russian Su-24 attack aircraft by a Turkish F-16 fighter jet on Tuesday posed the threat of more dogfights over Syria and dashed French hopes of a "grand coalition" with the U.S. and Russia to combat the Islamic State.
Russian President Vladimir Putin immediately called the incident over the eastern Turkish-Syrian border a "stab in the back" and warned of "serious consequences."
At a joint White House news conference with French President Francois Hollande, President Barack Obama said, "My top priority is to ensure this does not escalate" into more confrontations between the air arms of Russia and the U.S.-led coalition, which includes NATO ally Turkey.
However, he said, "Turkey, like every country, has the right to defend its territory and its airspace."
Hollande, who will go to Moscow on Thursday for talks with Putin, echoed Obama in saying that Russia was welcome to join the coalition but only if Putin dropped support of the regime of Syrian President Bashar al-Assad and focused on defeating ISIS.
U.S. officials said the downed jet was one of two Sukhoi Su-24s that were intercepted by two Turkish F-16s over the area where Turkey's Hatay province meets the Syrian border along the Mediterranean coast.
Turkish officials said the Su-24s had violated Turkish airspace. The F-16 fired only after at least 10 warnings to leave the area were ignored, the officials said.
Russian officials just as adamantly maintained that the Su-24 was fired upon without warning over Syrian territory. Video from the private Turkish broadcaster Haberturk TV showed the Su-24, a two-seat, swept-wing aircraft with the NATO code name "Fencer," trailing smoke and going down in flames in a wooded area.
U.S. officials confirmed that the Turkish planes gave at least 10 warnings.
"We could hear everything" that was said in the radio transmissions, and "the Russians didn't respond," said Army Col. Steve Warren, a spokesman for Combined Joint Task Force-Operation Inherent Resolve in Baghdad. He also said that there was no "mayday" emergency call from the Russian plane.
The fate of the two crew members of the Su-24 was unclear. Initial reports were that both crew members had ejected safely but were shot by ethnic Turkmens in the area as their parachutes neared ground. Other reports said one of the crew members may have survived.
Syrian activist groups also reported that the Russians may have suffered additional casualties in an effort by a Russian rescue helicopter to reach the two crew members.
The Free Syrian Army, which is opposed to Assad and has receive support from the U.S., released footage showing rebels using a U.S. "TOW" wire-guided anti-tank missile to destroy a Russian helicopter on the ground.
A narrator of the video shouted "Allahu Akbar," meaning "God is great," as the missile hit the helicopter. A Russian marine may have been killed in the attack, activist groups said.
Lt. Gen. Sergey Rudskoy, of the Russian General Staff, said that one Russian marine was killed when two Russian Mi-8 helicopters went on a search-and-rescue mission for the two Su-24 crew members. One of the helicopters was damaged by small arms fire and made an emergency landing in which the marine was killed, Rudskoy said.
"The helicopter was destroyed by mortar fire conducted from the territory controlled by illegal, armed groups," Rudskoy said.
At a news briefing, Peter Cook, the Pentagon press secretary said that Russian aircraft had violated Turkish airspace on two previous occasions since Russian aircraft, tanks and personnel began pouring into northern Syria in late September to back Assad.
Putin rejected charges that Russian aircraft had ever violated Turkish airspace. "Our plane was downed over Syrian territory by an air-to-air missile from a Turkish F-16 jet," Putin said, according to the Russian news outlet RT.
"The plane fell on Syrian territory four kilometers away from the Turkish border," Putin said. "It was flying one kilometer away from the Turkish border when it was attacked. In any case, neither our pilots nor our jet posed any threat to Turkey. That is obvious. They were carrying out an operation fighting against ISIL (another acronym for ISIS) in Northern Latakia."
Rudskoy, the Russian lieutenant general, condemned the attack as a "severe violation of international law." In response, military contacts with Turkey were being suspended and all Russian strike aircraft would now be accompanied by fighters, Rudskoy said.
In addition, the Russian missile cruiser Moskva was being sent to the eastern Mediterranean to provide more air cover for the Russian presence in Syria "with an aim to destroy any target that may pose a danger," Rudskoy said.
The French aircraft carrier Charles De Gaulle was also in the eastern Mediterranean and began launching strike missions in Syria on Monday with Rafale and Super Etendard jets.
The U.S. aircraft carrier Harry S Truman and its battle group left Norfolk, Virginia, last week amid speculation that the Truman would stop in the eastern Mediterranean to launch missions with the De Gaulle before taking up station in the Persian Gulf.
At the Pentagon, spokesman Cook said he could not confirm the Truman's mission or whether the use of the carrier was part of the discussions held Tuesday between Defense Secretary Ashton Carter and French Minister Jean-Yves Le Drian on closer cooperation in the fight against ISIS.
In Brussels, NATO's governing body, the North Atlantic Council, held an emergency meeting on the downing of the Russian plane.
NATO Secretary General Jens Stoltenberg later urged "calm and de-escalation" to resolve the Turkey-Russia confrontation while noting that Russian forces frequently came close in a menacing fashion to the borders of NATO allies.
"I have previously expressed my concern about the implications of the military actions of the Russian Federation close to NATO's borders," the NATO leader said. "This highlights the importance of having and respecting arrangements to avoid such incidents in the future."
At the White House, Obama commiserated with Hollande and the French people over the terrorist attacks claimed by ISIS earlier this month that killed at least 130.
Hollande pledged that France would join with the U.S. in intensifying airstrikes against ISIS but "France will not intervene militarily on the ground."
--Richard Sisk can be reached at Richard.Sisk@military.com