More than a dozen feared dead after a female suicide bomber blew herself up at a train station in Russia.

It was the second deadly attack in the space of three days as the country prepares to host the Winter Olympics.

Authorities say the bomber detonated her explosives in front of a metal detector just inside the main entrance of the train station in Volgograd.

Local media is reporting that President Vladimir Putin ordered law enforcement agencies to take all necessary measures to ensure security.