A controversial refereeing decision sparked violence and a crush at a soccer match in southeast Guinea, killing 56 people according to a provisional toll, the government said on Monday.

The fatalities occurred during the final of a tournament in honour of Guinea's military leader Mamady Doumbouya at a stadium in Nzerekore, one of the nation's largest cities.

Some fans threw stones, triggering panic and a crush, the government statement said, promising an investigation.

A video authenticated by Reuters showed dozens of people scrambling over high walls to escape.

Speaking on condition of anonymity, an official from the city's administration said many victims were minors caught in the turmoil after police started firing tear gas. The official described scenes of confusion and chaos with some parents retrieving bodies before they were officially counted.

Videos and pictures shared online showed victims lined up on the ground. In one video, over a dozen inert bodies could be seen, several of them children.

Reuters was not immediately able to verify that footage.

Opposition group National Alliance for Change and Democracy said authorities bore responsibility for organising tournaments to bolster political support for Doumbouya in contravention of a transition charter prior to a promised presidential election.

There was no immediate response from the military junta to that accusation.