Johannesburg, Feb 13: South African President Jacob Zuma on Tuesday defied an ultimatum from the ruling African National Congress to resign within 48 hours, pitching the nation into an unprecedented political crisis.

The decision to ask Zuma to stand down or face being stripped of his office was taken at a specially convened emergency session of the ANC's national executive committee (NEC) near Pretoria, the administrative capital, late Monday night, reports the Guardian.

The meeting was called after it became clear over that nearly five days of talks between Zuma, who has been the President since 2009, and Deputy President Cyril Ramaphosa, who took over the ANC's leadership in December, had failed.

After nearly 10 hours of heated debate, Ramaphosa and a key ally of Zuma left the meeting to drive to the President's official residence to deliver an ultimatum: stand down or face "recall", a technical term for the process of forcing an ANC official to leave their post.

If Zuma is ousted by a no-confidence vote, the speaker of parliament will serve as an interim President until elected representatives chose a new head of state.

However a "defiant" Zuma demanded a three month "notice period" before resigning, an ANC official told the Guardian.

A press conference has been announced at the ANC headquarters here later on Tuesday.

Zuma headed the ANC, the party that led South Africans to freedom from apartheid in 1994, from December 2007 to December 2017.

His nine years as President have been marred by economic decline and multiple charges of corruption that undermined the image and legitimacy of ANC.

However, the 75-year-old retains significant support inside the party and at a local level in many parts of South Africa, the Guardian reported.

Ralph Mathekga, a political analyst and author, said: "Zuma is not just a person. He is a system. There are a whole lot of people whose politics fortunes are tied to his.

"We are watching a battle for the soul of the ANC. It's a referendum on the true balance of power within the party."

South African President defies ANC's order to resign