South Africa's top prosecutor announced Sunday that she is withdrawing controversial murder charges against 270 miners for the killings of 34 striking co-workers shot dead by police.

The National Union of Metal Workers meanwhile demanded the suspension of the officers responsible for the shootings.

Sunday's announcement follows a barrage of criticism from political parties, trade unions, civil society and legal experts.

Even the justice minister had challenged the prosecutor's decision to charge the arrested miners under an apartheid-era law that opened President Jacob Zuma's government to accusations that it was acting like the former brutal white rulers.

Nomqcobo Jiba, the acting director of public prosecutions, did not say why she had reversed her decision to shift the blame from the police to the miners.

"The murder charge against the current 270 suspects ... will be formally withdrawn," she told a news conference.

She said the miners would be released from jail with a warning, providing police could verify their home addresses.

She said other charges, ranging from public violence and illegal gathering to illegal possession of firearms, would remain, but the cases were being postponed pending final investigations 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 Aug. 16 after police opened fire on striking miners, killing 34 and wounding 78. The shootings, the worst display of state violence since apartheid ended in 1994, shocked the nation.

Police said they acted in self-defense after the miners shot at them. Most miners were armed with homemade clubs and machetes but police said they recovered several handguns from the scene.

Ten people had been killed in a week of violence over union rivalries that preceded the shootings. Some of those killed were officials of the National Union of Mineworkers, two police officers were hacked to death and two mine security guards were burned alive in their vehicle.

Another union, the National Union of Metal Workers, which includes some miners, called for the suspension of the police task force "that executed the Marikana massacre."

The union's central committee "calls on the commission to find out and make public who, between the minister of police and the national police commissioner, gave orders to shoot workers with live bullets when they peacefully assembled on that fateful mountain," the union's secretary general Irvin Jim told a news conference Sunday.

He said the police shootings confirm that South Africa has not transformed "the apartheid state and its violent machinery." Apartheid ended 18 years ago.

Since then, South Africa has become the richest country on the continent, but the wealth has remained in the hands of minority whites joined by a small and often corrupt black elite.

The killings, and the plight of miners who were demanding higher wages, has highlighted the failures of Zuma's government just as he prepares to run for re-election in December as president of the governing African National Congress, a position that would virtually guarantee him another term as president.

Zuma's government is criticized for failing to address the concerns of South Africans suffering high unemployment, housing shortages and growing inequality between rich and poor.