South African President Thabo Mbeki has told his nation he did not interfere in attempts to prosecute a rival, AP reported. Mbeki's alleged role in the corruption case against African National Congress Jacob Zuma led his party to call on him to step down. In a nationally televised address Sunday, he said he had resigned, effective as soon as a new president is chosen. In the same address, Mbeki said «categorically» that he had never interfered in the work of prosecutors. He said that included «the painful matter» of the Zuma case.