Police at Lonmin's mine in Marikana in the North West had to use force in order to protect themselves, police said in a statement on Thursday.
"The South African Police Service was viciously attacked by the group, using a variety of weapons, including firearms," said Captain Dennis Adriao.
"The police, in order to protect their own lives and in self-defence, were forced to engage the group with force."
Adriao said this had followed extensive and unsuccessful negotiations by police to disarm and disperse a heavily armed group of illegal gathers at a hilltop near the mine.
"This resulted in several individuals being fatally wounded, and others injured."
The crime scene which covered a vast area was being managed by senior officials from the Independent Police Investigative Directorate (IPID) and supported by an expert team of detectives and forensic experts, he said.
National police commissioner Riah Phiyega and other senior members of management were currently at the scene as of late Thursday night, appraising themselves of the situation, which was still unfolding, said Adriao.
A press conference would be held on Friday at 11.30am at Lonmin Training Centre.
More than 30 miners were shot dead, Police Minister Nathi Mthethwa said on Friday.
"Police did everything they could... but people [miners] said they were not leaving and are prepared to fight," he said in an interview with Talk Radio 702.
Mthethwa told the broadcaster that more than 30 people were killed on Thursday afternoon when the police opened fire on armed mine workers who refused to disperse from a hilltop near the North West mine.
The minister said that "many" more were injured.
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