South Africa's ruling ANC party is to appoint a caretaker leader, after President Thabo Mbeki resigned on Sunday. A sombre Mr Mbeki, who took over from Nelson Mandela as president in 1999, was ousted by the party, deepening the worst political crisis since apartheid ended. The African National Congress asked Mr Mbeki to quit before the end of his term next year, eight days after a judge threw out corruption charges against party leader Jacob Zuma, suggesting there was high-level political meddling in the case. The political crisis may worry investors. South Africa's rand currency weakened in overnight electronic trading, trading 1.66 per cent lower at 8.0420 against the dollar. Mr Mbeki, who presided over South Africa's longest period of economic growth, said he remained a loyal ANC member and respected the party's decision but repeated that he did not influence the prosecution in the case of Mr Zuma, his rival. ANC treasurer-general Mathews Phosa said the party planned to announce an acting president on Monday. Parliamentary speaker Baleka Mbete is expected to be given the job. Mr Zuma, who holds no government post, is unlikely to have such an interim role and is all but certain to become head of state in 2009 elections. Mr Phosa said the ANC wants the cabinet to remain, underlining investor fears that the departure of experienced, pro-Mbeki ministers could hurt the country. "We want the Cabinet to stay. We are very happy if they stay and we do these things together," Mr Phosa said. Mr Mbeki has been credited with ensuring growth and attracting foreign investors to Africa's biggest economy. He was also instrumental in building a black middle class.