
The Russian imperial capital was beginning the first of three days of mourning and Russian tricolour flags flew at half mast throughout the city to honour the dead.
Flowers and candles piled up at an impromptu memorial outside the metro station hit by the attack as authorities beefed up security on the city's busy underground transport system.
Commuters began their daily trip to work under an anxious cloud after Monday's bombing that closed down the entire metro system that is seen as the lifeblood of the city.//AFP