South Africa's ruling party leader Jacob Zuma says he was a victim of abuse of power but has been vindicated as a court formally withdrew corruption charges against him.   But opposition parties are protesting the decision. 

The president of South Africa's ruling African National Congress, Jacob Zuma, told reporters the decision to drop corruption charges against him had proven his innocence.

"We thank all of them [supporters] for believing in my innocence, my assertions of a political conspiracy and of being a victim of a systematic abuse of power," Zuma said.

A high court in Durban formally withdrew the charges.  Zuma had been accused of accepting bribes to thwart an investigation into allegations of corruption in a multibillion dollar arms deal during the mid-1990s.

His financial adviser was convicted four years ago of fraud in the case and served a two-year prison sentence before being paroled last month.

But the National Prosecuting Authority dropped the charges against Zuma saying it had discovered evidence through secretly recorded telephone conversations that senior investigators had manipulated the process for political purposes.

The prosecutors said they believed the case still had legal merits, but the investigation had been irreparably tainted.

Zuma, who resigned as South Africa's deputy president four years ago because of the charges, said he had been vindicated.

"My conscience is clear," he said.  "I have not committed any crime against the state or the people of South Africa.  I had no difficulty with responding to the charges, as I knew they were baseless."

Zuma, as head of the ANC, is widely expected to become South Africa's next president in elections in two weeks.  He was to have gone on trial in August.

Zuma's supporters greeted the decision with street celebrations saying he could now assume the nation's highest office without the cloud of suspicion over his head.

But opposition parties objected.  They said the case against Zuma should continue and instead an investigation into the alleged interference should be launched.

One party, the Democratic Alliance, petitioned a high court to review the decision.

South Africa's election campaign has intensified with a new political party challenging the ANC in its traditional strongholds.

The Congress of the People, or COPE, emerged from a split within the ANC over the resignation last year of former President Thabo Mbeki, six months before the end of his last term.  Mr. Mbeki was obliged by the party to step down after a series of confrontations with Zuma supporters.