A female suicide bomber detonated explosives in the entrance hall of a Russian train station on Sunday,investigators said, killing at least 16 people in the second deadly attack within three days as the country prepares to host the Winter Olympics.
The attacker detonated a shrapnel-filled bomb in front of a metal detector just inside the main entrance of the station in Volgograd,a busy hub on Russias southern fringe.
Islamist militants in the North Caucasus have carried out a long string of attacks since President Vladimir Putin came to power in 2000. They now confront him with his biggest security challenge,threatening to disrupt the Olympics that start in the Black Sea resort of Sochi in 40 days.
The station was busier than usual,with people travelling home for New Year holidays.
People were lying on the ground,screaming and calling for help, a witness,Alexander Koblyakov,told Rossiya-24 TV. I helped carry out a police officer whose head and face were covered in blood. He couldnt speak.
Officials said the bomber was a woman who blew herself up after a police officer started to approach her near the metal detector because she looked suspicious.
A Russian website with ties to security agencies,Life News,posted a picture of what it said was the suspects head. It said authorities had identified her as a resident of Dagestan,the province adjacent to Chechnya and now the centre of a long-running Islamist insurgency.
So-called black widows,seeking to avenge fallen husbands,were involved in a deadly Moscow theatre siege in 2002 and have been behind several bombings including twin suicide attacks that killed 40 in Moscow in 2010.
An Investigative Committee spokesman said 16 people were killed in the attack,including two who died in hospital. Putin ordered law enforcement agencies to take all necessary precautions to ensure security,his spokesman said.