“The protracted and ever-increasing violent protest at Marikana, which culminated in the catastrophic and unprecedented loss of life, is to me regrettable,” said Phiyega on her first day of giving evidence.

She had been called to explain why police used deadly force, which resulted in the killing of the Lonmin platinum mineworkers on August 16 last year.

The killing, caught on camera, shocked the world and reminded many ion South Africa of apartheid-era brutality and further tarnished the image of the South African police.

Victims lawyers have told the commission, which is sitting in the northwestern platinum mining town of Rustenburg, that at least 14 of the miners were shot in the back, suggesting they were gunned down while fleeing from police.

Phiyega said the was informed by the regional police boss on August 13 that a “situation had developed” at the Marikana mine, where four people, including two security guards, had already died.

“This necessitated the deployment of more police officers to keep the peace,” said Phiyega.

Police have claimed they acted in self-defence when they opened fire on thousands of the miners who were gathered on a hill outside the mine, demanding wage increases.

“The events at Marikana have no precedent in the history of our organisation in democratic South Africa,” Phiyega said.

The police boss came under fire last year during the opening stages of the commission, when she was seen laughing while footage of the killings was shown on screens during the hearing.

On Thursday she denied she had been laughing.

The probe, headed by retired judge Ian Farlam, was convened last year by President Jacob Zuma and is expected to finish its work later in the year.