At least 13 people are reported to have died after a blast ripped through a train station in the southern Russian city of Volgograd.
The blast, captured on CCTV, shows a huge orange fireball filling the hall and smoke billowing out through shattered windows.
Russia’s state Investigative Committee said a female suicide bomber blew herself up in the entrance hall of the station, just in front of a metal detector.
President Vladimir Putin has ordered law enforcement agencies to take all possible measures to improve security, according to RIA news agency. Meanwhile, federal police spokesman, Vladimir Kolesnikov, has said security at train stations and airports would be stepped up further.
Two police officers who were checking the passengers are said to be among those who have died.
Investigators in Russia have put the death toll at 13, while the regional governor says 15 people have been killed as a result of the explosion.
Russian Health Ministry spokesman, Oleg Salagai, said as many as 42 people were wounded, with some needing to be flown to Moscow for treatment.
This is the second deadly attack in southern Russia in three days. On December 27, a car bomb in Pyatigorsk killed three people; while on October 21, 2013, a female suicide bomber also struck in Volgograd, killing seven people.
Sunday’s attack will bolster fears of attacks by Islamist militants as Russia prepares to host the 2014 Winter Olympics.
Volgograd lies close to Russia’s North Caucasus, a strip of mostly Muslim provinces plagued by near-daily violence.
In a video posted online in July, Islamist insurgent leader and Chechen warlord, Doku Umarov, urged militants to use “maximum force” to prevent President Putin from staging the Olympics.
The Games will be held in the Black Sea city of Sochi, around 690 kilometres from Volgograd, in February 2014.
Sunday’s attack was the deadliest to strike Russia’s heartland since Islamist insurgents killed 37 people at a Moscow airport in January 2011.