Two people were killed in a stampede Saturday at the South African stadium that hosted the 2010 World Cup final, during a match between the country's most popular teams, local media reported.
The incident occurred at a pre-season derby between Soweto rivals Kaizer Chiefs and Orlando Pirates.
Public and private broadcasters cited officials saying the crush took place outside a gate at the FNB stadium which hosted the final of the football extravaganza seven years ago.
"The city has been notified of two fatalities," said Luyanda Mfeka, the spokesman for the office of the mayor of Johannesburg.
He said the cause of the stampede was being investigated. Live television coverage of the match, which the Chiefs won 1-0, had shown no obvious disturbance.
She said several other people had also been injured when "a rolling mass of people were trying to get into the stadium" south of Johannesburg.
In a statement cited by an online football website KickOff, the match sponsors Carling Black Label also confirmed "two fatalities caused by blunt force trauma".
They said one fan was LAO critically injured and 16 other spectators suffered minor injuries.
The brewer said it was "saddened by the fatalities" from the crush caused by "a number of people who attempted to push through the stadium gates".
Match tickets were sold out two weeks before the game.
Local media reports suggested fake tickets had gone on sale, while some analysts said fans have a tendency to enter stadiums late.
"This incident is extremely unfortunate as solid security plans were put in place," Carling said in a statement.
Public and private broadcasters cited officials saying the crush happened outside a gate at the FNB stadium which hosted the final of the World Cup, seven years ago which was won by Spain.
'Extremely unfortunate'Hlomla Hlangani, an intern video journalist with public broadcaster SABC who was at the stadium, said the trouble occurred shortly after the match had started.
He said stadium security had to call in for police reinforcements after they were overpowered by a crowd of fans trying to rush through the gates.
He cited a witness he told him that 15 minutes into the match "there was lots of traffic to get inside the stadium... people were getting angry and some were drunk... and wanted to get into the stadium quickly".
Michael Sun, a Johannesburg municipal councilor responsible for public safety, spoke of a "stampede".
"Situation report from FNB Soweto Derby?Stampede reported with multiple injuries, 2 confirmed fatal," Sun wrote on Twitter.
Police have launched investigations into the fatal incident.
The match carried on despite the tragedy at the stadium, which has an official capacity of 94,000, and was won 1-0 by the Kaizer Chiefs.
South African Football Association (SAFA) said it was "deeply saddened by the tragedy".
"A football match is supposed to be a place of entertainment. What happened at FNB Stadium is very unfortunate," SAFA president Danny Jordaan, said in a statement.
The two worst football tragedies in South Africa involved matches between the same clubs -- in 2001 when 43 people were killed, and in 1991, when the death toll was 42.
The worst football tragedy in the World occurred in 1964 in Lima during an Olympic qualifier between Peru and Argentina at the National Stadium. The official toll was 328 dead.
In April 2001, a similar stampede saw 63 people crushed to death at Ellis Park, venue for the 1995 Rugby World Cup final, when Chiefs and Pirates met in a midweek league match. It was the country's worst sporting tragedy and came as spectators broke through fences in an effort to get into the stadium.
Chiefs and Pirates are South Africa's best supported clubs and have a rivalry stretching back almost 50 years. Saturday's match was a traditional pre-season friendly between the two clubs.