Volgograd blasts: Second suicide bomb hits Russia city
At least 14 people have been killed
in a suicide bombing on a trolleybus in the Russian city of Volgograd,
investigators say.
The blast comes a day after 17 people died in another suicide attack at the central station in the city.
Security has been tightened at railway stations and airports across Russia.
Moscow is concerned that militants could be ramping up violence in the run-up to the 2014 winter Olympic Games in the city of Sochi in February.
For most Russians, these attacks came as a huge shock. Bombs in public places
seemed to have become a thing of the past.
Russian state-controlled media had been telling the public that the insurgency was under control, and that the Sochi games would be "the safest in history". But after the Volgograd bombings, most commentators are now questioning these promises.
Many security experts say Russia's secret services have become complacent - that they have spent too much time trying to weaken President Putin's political opponents, and too little time trying to infiltrate extremist cells in the Caucasus.
Hundreds of police officers and military personnel are now being moved into position, taking control of roads, railways and even mountain paths in the area.
But while the threat to the Games in Sochi may not be that big, the fear is that the bombers may strike elsewhere. And in Moscow, as well as in Volgograd, there is a palpable sense of unease.
Russian state-controlled media had been telling the public that the insurgency was under control, and that the Sochi games would be "the safest in history". But after the Volgograd bombings, most commentators are now questioning these promises.
Many security experts say Russia's secret services have become complacent - that they have spent too much time trying to weaken President Putin's political opponents, and too little time trying to infiltrate extremist cells in the Caucasus.
Hundreds of police officers and military personnel are now being moved into position, taking control of roads, railways and even mountain paths in the area.
But while the threat to the Games in Sochi may not be that big, the fear is that the bombers may strike elsewhere. And in Moscow, as well as in Volgograd, there is a palpable sense of unease.
The Olympics venue is close to Russia's volatile north
Caucasus region, and the BBC's Moscow correspondent Daniel Sandford says it was
always risky staging the Games so near to the troubled republics of Chechnya and
Dagestan.
These bombs have been a brutal reminder of that, he says.
But a spokeswoman for the International Olympic Committee told Reuters news agency that the organisation had no doubt Russian authorities would provide adequate security for the Games.
Busy market
The latest explosion took place near a busy market in Volgograd's Dzerzhinsky district.
Maksim Akhmetov, a Russian TV reporter who was at the scene of the blast, said the trolleybus was packed with people going to work in the morning rush hour.
He described the scene as "terrible", adding that the bus was "ravaged" and that there were "bodies everywhere, blood on the snow".
Witnesses described a scene of carnage following the
blast 
Police cordoned off the site of the explosion as they
looked for clues 
The explosion was the second in the city in 24 hours.
A blast hit a train station on Sunday. 
Sunday's explosion blew out many windows, and sent
debris down the station steps The figures given for the number of dead and injured are still fluctuating, but investigators and the Russian health ministry told a press conference that 14 people had been killed.
At least 20 others were injured, and Health Minister Veronika Skvortsova said the patients were in "a bad condition with burns, with multiple injuries typical of blast-induced wounds".
She said the injured include a pregnant woman, two 16
year olds and a baby aged about six months whose parents are assumed dead.
The regional governor has announced five days of mourning for all the victims.
The force of the explosion removed much of the bus's exterior and broke windows in nearby buildings.
"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 Investigative Committee said in a statement.
City in shock
In response to this second blast in less than 24 hours, Russian President Vladimir Putin has ordered security measures to be tightened across Russia and in particular in Volgograd.
Local resident Polina Goncharova said the whole city was in shock.
"This is the first time in my life that I have experienced anything like this. I have been crying since I heard about the first bombing, and now the second one today," she told the BBC.
"There are very few people on the streets. I am staying at home myself as I'm worried there will be more attacks."
