Female suicide bomber set off a blast in a train station in the southern Russian city of Volgograd that killed at least 14 people, news reports and officials said.
Regional Interior Ministry spokeswoman Svetlana Smolyaninova told the ITAR-TASS news agency on Sunday that the blast occurred inside the city's main train station at around 12:45pm (8:45 GMT).
Vladimir Markin, the spokesman for the nation's top investigative agency, the Investigative Committee, said the suicide bomber detonated her explosives in front of a metal detector.
"When the suicide bomber saw a policeman near a metal detector, she became nervous and set off her explosive device," Markin said in a statement.
He added that the bomb contained about 10 kilograms of TNT explosives and was rigged with shrapnel.
Markin said that security controls prevented a far greater number of casualties at the station, which was packed with people at a time when several trains were delayed.
Markin put the death toll at 14, while Volgograd's regional governor, Sergei Bozhenov, said 15 died. Russia's Health Ministry said about 50 people were injured.
The city of Volgograd, known as Stalingrad in the Soviet era, was attacked in October by a female suicide bomber with links to groups fighting federal forces in Russia's volatile North Caucasus.
The October 21 strike killed six people aboard a crowded bus and immediately raised security fears ahead of the February 4-23 Winter Games in Sochi.
The Black Sea city that will host the Olympics lies 690km southwest of Volgograd and in direct proximity of the violence ravaging North Caucasus regions such as Dagestan and Chechnya on a daily basis.
'Black widows'
Fighters are said to be seeking to impose an Islamist state throughout Russia's North Caucasus.
Their leader Doku Umarov has ordered his foot soldiers to target civilians outside the region and disrupt the Olympic Games.
Female suicide bombers are often referred to in Russia as "black widows", women who seek to avenge the deaths of their family members in North Caucasus fighting by targeting Russian civilians.
Female suicide bombers set off blasts at two Moscow metro stations in March 2010 that killed more than 35 people.
They were also responsible for taking down two passenger jets that took off from a Moscow airport within minutes of each other in 2004, killing about 90 people.
Source:Al Jazeera and agencies
