The bodies of victims of a suicide bomb attack on a Russian train station Sunday are laid outside as investigators examine the scene.
A shrapnel-filled bomb was detonated by an assailant in front of a metal detector inside the entrance hall of this station, killing 16 people.
The blast blew out nearby windows.
Authorities initially said the attacker was a woman, but later said a man could have set off the blast.
Cleanup operations continued well into the night and security stayed on site.
Deadly attacks like these, the second in three days, pose a security challenge for President Vladimir Putin now that the Russian winter Olympics are 40 days away.