Investigators consider three main versions, a terrorist act, criminal showdowns and the assassination of certain people, Mr. Gerasimov told journalists. However, the third version is hardly plausible, he added.
In his words, chemical examination of the explosive device is underway. It contained at least 1 kg of plastic explosives.
According to Samara medics, the explosion killed 10 people. 32 persons were hospitalized and three of them are in critical conditions. One woman has not rallied from the coma yet.
Prosecutor's, police and FSB (Federal Security Service) officers are involved in the investigation.
The Kirov market is working in normal regime today. Cordons were put around the blast site. Extra security measures are taken at Samara markets and the railway station.
The explosion at the Kirov market blasted at 12.04 Moscow time.
The explosive device was laid between two booths on a concrete fence looking on the railroad, said Alexander Yefremov, prosecutor of the Samara region.
The explosion was directed towards the railroad with Diesel fuel tanks. The tanks reflected the blast wave and it prevented the ignition, he noted.