Witnesses allege police brutality in shooting of striking miners at Marikana mine last month that left 34 people dead.

Al Jazeera has learned that some of the South African miners who were shot dead at the Marikana mine last month may have been trying to surrender.

At least 34 men died when police opened fire on striking workers at the platinum mine, 100km north of Johannesburg.

A key human rights organisation in South Africa launched an independent investigation into the police shootings on Sunday.

The Legal Resource Centre (LRC) said that it had obtained multiple witness testimonies that blame police brutality for the killings of strikers who were calling for pay raises.

Some witnesses have said that police shot protesters who were either trying to escape confrontations with police by hiding behind rocks, or while surrendering to authorities.

The LRC also said it has forensic evidence that suggests a police cover-up of the killings.

On August 16, police opened fire on a crowd of miners engaged in a strike at the Lonmin platinum mine in Marikana.

Video showed a densely packed crowd of miners, some armed with clubs and machetes, approaching heavily armed police, who claimed self-defence in the shooting.

The incident was the climax of an escalating stand-off between rival unions that had already killed 10 people, including two police officers.

‘Allegations of torture’

Government officials and police officers have repeatedly rejected Al Jazeera’s request to comment on the allegations, saying they would not speculate until a judicial inquiry into the incident was complete.

Danny Titus, from the South African Human Rights Commission, discusses the Marikana shooting

Danny Titus, a representative of the South African Human Rights Commission, told Al Jazeera that the organisation was very concerned with allegations of human rights violations.

“We are really concerned about the allegations coming from the miners, really giving us so much detail about what really happened,” he said.

Titus added that if the allegations were proven to be true, it would suggest that the workers were shot “out of vengeance”.

“There was not a crowd-control approach [by police]. These police already went before parliament to explain themselves, and one of the first kind of defences they put forward was the fact they did not have training in crowd-control very high in their priority, which is very strange.”

“And beyond that there are further allegations of torture [of striking miners].”

Meanwhile, striking mine workers say they will not return to work until their demand for more pay is met, the leader of a key union said.

Workers are facing a Monday deadline to return to the Lonmin PLC mines, paralysed by a four-week strike that has sent company shares plummeting, raised world platinum prices and stoked worries of labour unrest spreading through the mining sector of Africa’s largest economy.

“When the employer is prepared to make an offer on the table, we shall make ourselves available,” Joseph Mathunjwa, president of Association of Mineworkers and Construction Union (AMCU), told a news conference on Friday.

Peace accord

Mathunjwa was responding to his union’s decision not to sign a “peace accord” with its rival National Union of Mines (NUM) and the mine’s management on Thursday.

Miners were demanding a huge pay rise and

recognition of a new union [Al Jazeera]

While AMCU says it represents about 7,000 workers, Mathunjwa, told reporters that he supported the workers but could not speak on their behalf, according to local media reports.

Negotiations on the wage demand will begin on Monday. Gideon du Plessis, general secretary of Solidarity, one of the unions that have signed the accord, said that all parties involved, including AMCU and representatives of the striking workers, have been invited to the negotiations.

“Solidarity now appeals to the striking workers to comply with the requirements for the negotiations, namely to lay down their arms and to return to work by Monday, so that their demand could be addressed.”

On Friday, Lonmin said two per cent of shift workers reported to their posts. Miners have said they have been threatened by striking miners with death if they go back into the shafts.

About 3,000, mostly rock drill operators, of Lonmin’s 28,000 South African workforce walked off their jobs. They were demanding a monthly base pay of 12,500 rand ($1,500), which is double current wages, an amount analysts said the financially strapped company cannot afford.