Mbeki is to leave office when "all constitutional requirements have been met," said aide Mukoni Ratshitanga.

Mbeki has scheduled a Cabinet meeting for Sunday and Parliament is expected to meet this week to formalize his resignation, the BBC reported Saturday.

The ANC increased pressure on Mbeki to resign after a High Court earlier this month suggested Mbeki may have interfered in a corruption case against his rival and ANC leader Jacob Zuma, who is favored in polls to become the country's next president in elections next year, The Washington Post (NYSE:WPO) reported.

Mbeki, who has denied he influenced the case against Zuma, succeeded Nelson Mandela as the party's leader in 1997. He became president of South Africa in 1999 and was re-elected to a second term in 2004.