At least nine killed as a result of violent protests between rival unions at platinum mine northwest of Johannesburg.

At least nine people, including two police officers, have died as a result of clashes between the members of two rival unions at a platinum mine in South Africa, police have said.

Two police officers were killed during the violence between the National Union of Mineworkers (NUM) and the Association of Mineworkers and Construction Union (AMCU) on Monday, while another remained in critical condition, Lindela Mashigo, a police spokesman, told AP news agency.

“Our police officers were responding to a protest at the mine. They came under attack from the workers and two of them were hacked to death,” he said.

“There is talk of a rival union involved in the violence. We never called for a strike in this mine. What happened was that a small group of workers wanted a strike and when they didn’t get their way, they resorted to violence. All the workers who died, except for the police officers, belonged to our union The duty of the union is to engage with our employers and not criminals. And we are hoping that the police agencies will be taking up the matter.” Lesiba Seshoka, NUM’s spokesperson, speaking to Al Jazeera

“Officers opened fire on the crowd, killing at least three people, he said.

Authorities struggled to control the clashes at Lonmin’s mine operation near Marikana, a town about 70km northwest of Johannesburg, with rioters at one point overpowering officers and stealing their weapons, police said.

Protests began on Friday at the mine when workers walked off the job over a salary dispute, Lonmin said in a statement on Monday.

Four workers from a rival union attempting to go to work were then attacked by the original strikers.

Angry protesters returned to the mine on Sunday, killing two security guards by setting their car on fire, authorities said.

Another two miners died on Monday in other attacks, police and company officials said.

Lesiba Seshoka, NUM’s spokesman, said the fighting had shut down Lonmin’s operation near Marikana.

“The situation is tense,” Seshoka said.

A spokesman for the AMCU could not be immediately reached for comment.

Solidarity, a union that largely represents skilled white workers, said in a statement on Monday that three of its members had been injured in the protests.

The union also threatened to pull its workers from the site if calm was not restored.

The restive labour force is among many challenges facing the mining industry, which has been weakened by decades of under-investment.

A debate over nationalisation and other policy questions have created uncertainty that has scared off potential investors.

South Africa remains a major producer of platinum, coal and gold.

Lonmin, the world’s third largest platinum producer, says 96 per cent of all of its production comes from its Marikana operations.