SAMARA, June 4: Nine people were killed and more than 40 others injured on Friday when a powerful explosive device went off outside a bustling open-air market in the central Russian city of Samara, officials said.

The authorities initially said the market blast had probably been set off by two faulty gas canisters, but changed their theory after Federal Security Service (FSB) agents inspected the site. Local prosecutors have now opened a criminal inquiry for acts of terrorism and murder.

"We have dismissed the possibility that this was caused by gas canisters. Our main hypothesis now is that it was an act of terrorism," a local police spokesman said. "There was a very powerful explosion and a great ball of yellow fire went up many metres into the air," one frightened female vendor said. -AFP