The wreckage of the bus was so mangled that hours later emergency workers were still trying to get into it to check for victims, police spokeswoman Elizabeth Kanjela was quoted as saying.
Some fans complained about difficulties getting around the city, with delays caused by traffic congestion and long queues to check in to hotels - despite efforts by the Russian authorities to ease their way, with special buses and bus lanes to ensure fans do not get caught in rush hour jams.