Police and politicians say four miners were injured by rubber bullets at a South African gold mine, while another group of workers have been released from prison following unrest at another mine in the country last month.

The four miners were apparently shot by security guards using rubber bullets at the Gold One mine east of Johannesburg. The company's CEO, Neal Froneman, told BBC News that the four have now been discharged from hospital. He said they are ex-employees of the mine and had been fired after an illegal strike in June.

Police spokeswoman Pinky Tsinyane confirmed four miners were shot and that police have arrested four people for public violence.

The latest violence comes on the day of the release of scores of miners who were arrested in the killings of their coworkers during clashes with police on August 16. Thirty-four striking miners at a platinum mine were killed by police bullets but 270 of their colleagues were arrested in connection with the deaths.

Nomqcobo Jiba, the acting director of public prosecutions, said Sunday she would drop the murder charges against the 270 miners in connection with the killings at the Lonmin PLC Marikana platinum mine. Up to 100 of the miners were expected to be released on Monday.

Jiba said the miners would be released from jail, providing police could verify their home addresses. The rest of the miners could be released on Thursday once they make a court appearance on other charges.

She said the other charges, which range from public violence and illegal gathering to illegal posession of firearms, would stand. However, the cases were being postponed pending investigation, and the findings of a judicial commission of inquiry, which is to report to the president by January.

Most of the 270 miners were arrested after police opened fire on striking workers, killing 34 and wounding 78. The shootings were the worst display of state violence since apartheid ended in 1994.

Police said they acted in self-defence after the miners shot at them.

The unrest at South Africa's mines continued elsewhere on Monsy, with some 2,000 miners at the Gold Fields company mine west of Johannesburg walking off the job.

Mining companies say the unrest stems from an internal labour battle between the officially recognized National Union of Mineworkers and a more radical new union — the Association of Mineworkers and Construction Union.

With files from The Associated Press