The owner of the South African mine where 34 striking workers were shot dead by police a year ago has apologised to relatives.
"We will never replace your loved ones and I say we are truly sorry for that," Lonmin boss Ben Magara said.
He was speaking to thousands of people gathered to mark the anniversary of the deaths at the Marikana platinum mine.
South Africa's governing ANC is not attending the commemorations, saying they have been "hijacked".
The ANC pulled out at the last minute, accusing some of "taking advantage of a tragedy for their own political benefit".
At the ceremony, Mr Magara, head of the world's third largest platinum producer, said:
"It should not have to take the loss of so many lives for us as a company, as employees, as a community and as a nation to learn that this should have never happened and that it should never happen again."
"Each day we feel the effects of this tragedy," he added.
The BBC's Pumza Fihlani in Johannesburg says the apology makes a shift of attitude from Lonmin.
The company has been criticised for not taking any ownership of the events that led to last year's killings or apologising, she says.
The shootings were the deadliest use of police force since the ANC came to power in 1994, ending white minority rule.
The government was criticised for its handling of the crisis, which shocked South Africa and hit confidence in the mining sector.
Rivalry between two unions - one allied to the ANC - was at the heart of the unrest.
The pro-ANC National Union of Mineworkers has been displaced as the majority union in the Marikana mine by the more militant Association of Mineworkers and Construction Union (Amcu).
"The ANC finds it immoral and totally unacceptable that such a traumatic incident could be turning into a political playground" by its opponents, it said in a statement.
Government officials were also absent from the events, organised by Amcu, which called last year's unofficial strikes and is again pushing for substantial wage increases.
Several opposition leaders, including firebrand youth leader Julius Malema, sat with the miners' widows.
Some in the ANC fear that Amcu could form an alliance with Mr Malema, who was expelled from the ANC last year and who recently formed a new political grouping.
Mr Malema, who fell out with South African President Jacob Zuma and accused him of ignoring poor black South Africans, was loudly cheered when he arrived.
Thousands of mine workers gathered at the rocky hill, or koppie, where their colleagues were killed last year, singing songs and listening to speeches.
Religious leaders held prayers and a minute's was scheduled around the time when the police opened fire on the striking miners.
The police say they feared they would be attacked by a mob armed with machetes, sticks and other weapons during last year's dispute.
In the week before the shootings, 10 people had been killed during violent protests, including two security guards and two police officers.
President Zuma set up a commission of inquiry to investigate the events leading to the killings.
But some of the Marikana miners are angry that not a single policeman has yet been arrested over the shootings.
Correspondents say that while talks between the government, unions and business have yet to produce stability, an atmosphere of violence and intimidation endures in the area.
Earlier this week, a senior NUM official was shot dead near the mine.