ANC president Jacob Zuma looks on at the National Assembly in Cape Town…ANC president Jacob Zuma looks on at the National Assembly in Cape Town, September 25, 2008. South Africa’s parliament began voting on Thursday for an interim state president, widely expected to be ruling ANC deputy leader Kgalema Motlanthe, after the country suffered its worst political crisis since apartheid ended. The vote comes after the resignation of Thabo Mbeki as head of state on Sunday. REUTERS/Nic Bothma/Pool (SOUTH AFRICA)

South African state prosecutors said Monday they would appeal against a court ruling that President Jacob Zuma should face almost 800 corruption charges, setting up a legal battle that could threaten his hold on power.

The charges, relating to a multi-billion dollar arms deal, were dropped in 2009, clearing the way for Zuma to be elected president just weeks later.

At the time, state prosecutors justified dropping the charges by saying that tapped phone calls between officials in then-president Thabo Mbeki’s administration showed political interference in the case.

But the Pretoria High Court court last month dismissed the decision to discontinue the charges against Zuma as “irrational” and said it should be reviewed by the National Prosecuting Authority.

“I have decided to apply for leave to appeal against the judgement of the full bench of the Pretoria High Court,” Shaun Abrahams, director of the NPA, told a press conference on Monday.

Zuma has endured months of criticism and growing calls for him to step down after a series of corruption scandals amid falling economic growth and record unemployment.

Pressure on the president would increase if some or all of the 783 charges — which relate to alleged corruption, racketeering, fraud and money laundering — were reinstated.

Last month, a commission that Zuma set up cleared all government officials — including himself — of corruption over the 1999 arms deal.