The suicide bomber set off a device containing about 22 pounds of TNT and shrapnel near a metal detector at a railway station in Volgograd, according to government spokesman Vladimir Markin. About 40 people have been hospitalized, the Associated Press reports. No one immediately claimed the attack, and it was not clear where the bomber was from.

　　The bomber’s head was discovered on site, which authorities said will help with quick identification. Reports about the bomber’s gender have been conflicting, with officials saying the bomber was a woman, but other sources saying surveillance camera footage showed the bomber was likely a man.

　　Russia has deployed thousands of soldiers and police to secure the region of Sochi, where the 2014 Winter Olympics begin on Feb 7. The attack, 400 miles northeast of Sochi, comes several months after Chechen rebel leader Doku Umarov urged his men to launch new attacks on Russian civilians, and to “do their utmost to derail” the Olympics.

　　President Vladmir Putin has heightened security efforts including drones to monitor Olympic facilities, speed boats and special troops to patrol both the coast and the mountains nearby. Olympic vistitors must obtain a spectator pass to attend the games, which includes providing passport details and contacts as a part of a screening process.

　　Read more: Suicide Bomber in Russia Kills 14, Injures Dozens | TIME.com http://world.time.com/2013/12/29/suicide-bomber-in-russia-kills-14-injures-dozens/#ixzz2ovFUKP6n