Fourteen people have been killed in a bus explosion in Volgograd, a day after a suicide bombing left at least 17 dead at a railway station in the same Russian city.
The morning rush hour blast, which federal investigators have called a "terrorist act", reduced the trolleybus to a twisted, gutted carcass, its roof blown off and bodies and debris strewn across the street.
Russian investigators said they believe the explosion was caused by a male suicide bomber who detonated the bomb in the vehicle's passenger area.
"It is now possible to preliminarily say that the explosive device was set off by a suicide bomber - a man whose body fragments have been collected and sent for genetic testing," the federal Investigative Committee said in a statement.
The two explosions in close concession have put the city on edge and highlighted the terrorist threat that Russia faces, as it prepares to host the Winter Olympics in February.Reuse content