daniel griffin has the latest. >> in downtown rio de janeiro, a street turned to rubble. cars buried where they were parked. all of this in just a few devastating moment. >> i was walking on the path when suddenly the building collapsed. it was connected to the other building and it just collapsed. so we ran out. we try to see if there was anybody inside, but we could not tell. >> at first, i thought someone was trying rubble, that it was nothing serious. then i started to take some steps back and suddenly, the building collapsed. it came down completely. >> emergency services have begun a rescue operation. some people have been pulled alive from the wreckage. nobody knows how many more are still trapped. what caused this is still unknown. some officials have blamed it on structural faults. witnesses said they smelled gas and heard an explosion just before the collapse. some of the rubble is already been cleared and this the latest in a series of accidents that have raised concern about the city's infrastructure. as it prepares to host both the world cup and the olympics

theably zards in bulgaria, romania and serbia has caused travel chaos as daniel griffin reports. >> blizzard and sub zero temperatures. much of the region going nowhere. some areas are now under meters of snow. travel all but impossible. at the arnte, many flights were canceled. train services also disrupted. conditions on the roads aren't much better. many, impossible. some drivers stranded. others simply gave up. emergency services are facing a huge challenge. snow has been falling in some areas for weeks. >> we've had a state of energy place since when the snow started to fall. it's now more than three weeks. we're clearing roads, helping people and bringing them food and med sifpblet >> there's little prospect of an improvement with more snow forecasted. >> this is "bb crs news." still ahead with six months to go before the start of the 2012 olympics, we'll have a look at the preparations for the opening ceremony in london. >> to south sudan now where just six months after declaring independence the government says it will completely shut down all production in just two days. as a landlo