As tens of thousands of Russian tourists hastily leave Egypt's economically vital seaside resorts, a top Kremlin official issued an ominous warning on Tuesday: They're not coming back anytime soon.

Russia last week suspended all passenger flights to Egypt in the wake of the Oct 31 airliner crash in the Sinai Peninsula that killed all 224 people on board, almost all of them Russians. Moscow said the ban was necessary because of concerns about security at Egypt's airports.

Russian officials said they haven't determined whether a bomb brought down the plane as it flew from Sharm al-Sheikh toward St. Petersburg. But the flight ban and unspecified concerns about airport security suggest Russia takes the prospect exceptionally seriously.