Six killed in southern Russia bus blast: ministry

Six people were killed and several others injured today when a blast tore through a passenger bus in the southern Russian city of Volgograd, officials said.
"The toll has risen to six killed and seven injured," a Russian Federal Security Service (FSB, ex-KGB) spokesman told AFP by telephone.
A regional emergencies ministry spokeswoman separately told AFP that 17 people were injured by the blast.
Officials said the blast occurred at around 2:00 pm (1000 GMT) in the city on the Volga River, located about 900 kilometres southeast of Moscow.
"There were around 40 people on board," said the FSB official, adding that investigators could not yet pinpoint the cause of the explosion.

The state-run Rossiya 24 rolling news channel said investigators were probing whether the blast may have been caused by a leaking gas canister used by some city transport vehicles as a source of fuel.

"According to preliminary information, the gas equipment (on the bus) blew up," a Volgograd police department spokesman separately told the state ITAR-TASS news agency.
But the Interfax news agency cited an unnamed security source as saying that an explosive device may have been planted on the bus.
"According to preliminary information, it was an unidentified explosive device. So we are looking at an act of terror as one possibility," the unnamed security source told Interfax.

Security remains a concern throughout southern Russia ahead of next year's Winter Olympic Games in the Black Sea resort of Sochi, which is located next to the restless North Caucasus region.