Anna Fedoseyeva, spokeswoman for the airport in Russia's second-largest, city said the evacuation of passengers and staff began at 3 pm local time. She said the airport was still receiving incoming flights but passengers were not allowed to disembark.
Transit police of the north-west region said the airport received an anonymous telephone bomb threat at 1.30 pm and that a bomb squad was searching the terminal.
Bomb threats are common in Russia, mostly the work of teenage pranksters, but evacuations of airports or railway stations are rare.