Days before Jacob Zuma was expected to become the next leader of South Africa's ruling ANC, legal authorities have filed court documents they say contain new evidence against him in a corruption case.
The Directorate of Special Operations has filed an affidavit in the Constitutional Court containing what it called substantial new evidence that Mr Zuma had received larger payments in a corruption case than originally thought.
"The extent and gravity of the charges has grown...," said the affidavit, which was a response to an appeal by Zuma.
"The payments based on the old and the new evidence are therefore more than three times greater than those based on the old evidence alone."
Mr Zuma appears headed for victory after taking a strong lead in branch nominations over his rival President Thabo Mbeki in the race to lead the African National Congress.
A win would virtually assure him the South African presidency in the 2009 general election because of the ANC's electoral dominance. The party will elect a new leader during a four-day conference which started to today. A vote is expected tomorrow.
Reflecting the concern of party veterans, former ANC leader Nelson Mandela told delegates in a message that he was saddened by the differences emerging in the party.
Mr Mbeki, who took over the party from Mr Mandela in 1997 accused some members of dishonesty.
"This is the practice that again is entirely foreign to our movement - the practice of using untruths, of resorting to dishonest means and deceit to achieve particular goals," Mr Mbeki said.
Mr Zuma has made a dramatic political comeback despite the corruption allegations and a rape trial in which he was acquitted in 2006. The latest legal push against him could give Mbeki political ammunition but analysts say Mbeki is unlikely to break Zuma's momentum.
If he is is re-charged with corruption, it raises the prospect South Africa's future president could be jailed long before he is sworn in. Mr Zuma has said if he wins the ANC'S top job, he would step down only if a court proves he is guilty.