it is a world war with no conventional boundaries or defined lines
The Sinai is under the defined control of the Egyptian govt so the Russians should expect full cooperation in an investigation and a brisk security response by Egypt if required
However, it seems uncomfortably similar to the Ukrainian aircraft disaster and a plane load of highly level islamist mucka muckas was just downed in Libya in the past week or so
1983: Soviet jet fighters intercept a Korean Airlines passenger flight in Russian airspace and shoot the plane down, killing 269 passengers and crewmembers. The incident dramatically increased tensions between the Soviet Union and the United States.
http://www.history.com/this-day-in-history/korean-airlines-flight-shot-down-by-soviet-union
Among the victims were the President of Poland Lech Kaczynski and his wife Maria, the former President of Poland in exile Ryszard Kaczorowski, the chief of the Polish General Staff and other senior Polish military officers, the president of the National Bank of Poland, Polish Government officials, 18 members of the Polish Parliament, senior members of the Polish clergy and relatives of victims of the Katyn massacre.
The group was arriving from Warsaw to attend an event marking the 70th anniversary of the [Katyn] massacre, which took place not far from Smolensk."
https://en.wikipedia.org/wiki/2010_Polish_Air_Force_Tu-154_crash
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April 2014...
Did Putin Blow Up the Whole Polish Government in 2010?
A Second Look
A plane crash at Smolensk in Russia four years ago wiped out the Warsaw leadership. It used to be seen as an accident. Now, after Putin's games in Ukraine, people aren't so sure.
Four years ago this week, Polish President Lech Kaczynski was killed in a plane crash near the Katyn Forest in Russia where he was flying to honor the 22,000 Polish officers, lawyers, priests and professors slaughtered there by the Soviets 70 years before. Ninety-five other military, political and public figures including his wife died on that plane. One of the more heartbreaking details to emerge was that First Lady Maria Kaczynska's body could be identified only by her nail polish and the inscription inside her wedding ring.
Less than two years before the crash the late president had given a speech warning that if Russian aggression was not stopped in Georgia, which Russia had invaded, it would extend to Ukraine, the Baltics, and possibly Poland as well. "We are here to take up the fight," he said. And many Poles still believe that their president died in the cause of that effort. Physicist Kazimierz Nowaczyk is one of them. ..."
(BIG SNIP)
He makes the case at the link...
Did Putin Blow Up the Whole Polish Government in 2010? A Second Look:
http://www.thedailybeast.com/articles/2014/04/11/did-putin-blow-up-the-whole-polish-government-in-2010-a-second-look.html