President Jacob Zuma of South Africa has announced an inquiry into trouble at a platinum mine in the north-east of the country.
Thirty four people were killed when police opened fire on striking miners on Thursday. At least 78 others were wounded in the confrontation.
Mr Zuma said he was "saddened and dismayed" and offered condolences to all families who had lost loved ones.
"We have to uncover the truth about what happened here,'' he said. ''I have decided to institute a commission of inquiry. It will enable us to get to the real cause of the incident and derive the necessary lessons."
The president said his thoughts were with the families of those who had lost their lives, but also with the police "who have to intervene in difficult situations".
Mr Zuma added:
''Today is not an occasion for blame, finger-pointing or recrimination. Today challenges us to restore calm and to share the pain of the affected families and communities. Today is about reminding ourselves of our responsibility as citizens.''
The president said it was a "cornerstone of hard-won democracy" to allow for peaceful protests, but added that today was "a day for us to mourn together as a nation - a day to start rebuilding and healing".
Mr Zuma cut short his attendance at a regional summit in Mozambique to deal with the crisis.
The shooting took place at a platinum mine in Marikana, owned by Lonmin.
A strike there began a week ago and had claimed the lives of 10 people, including two police officers, before Thursday, when officers opened fire on strikers armed with spears and clubs.
Police defended themselves
Police say the officers fired in self defence. Two officers were killed at Marikana last week.
Eyewitness reports suggest the shooting took place after a group of demonstrators rushed at a line of police officers. Dozens of shots were fired.
Police chief Riah Phiyega said officers "were forced to use maximum force to defend themselves".
On Thursday, Lonmin said that the strike meant it would lose 15,000 ounces of platinum production, and as a result it was unlikely to meet its production forecasts for the full year.
Platinum is used to make electrical components, jewellery and catalytic converters in motor vehicles which reduce carbon emissions.
Shares in Lonmin ended the week down more than 10% in London.