Jacob Zuma is expected to face a no-confidence vote in parliament if he does not stand down.

Jacob Zuma has defied an ultimatum from South Africa’s ruling party to resign within 48 hours, pitching the “Rainbow Nation” into an unprecedented political crisis.

The decision to tell Zuma to stand down or face being stripped of his office was taken at a specially convened emergency session of the highest decision-making body of the African National Congress near Pretoria, the administrative capital, late on Monday evening.

The meeting of the ANC’s national executive committee (NEC) was called after it became clear over the weekend that nearly five days of talks between Zuma, who has been South Africa’s president since 2009, and the deputy president, Cyril Ramaphosa, who took over the leadership of the ANC in December, had failed.

After nearly 10 hours of heated debate, Ramaphosa and a key ally of Zuma left the meeting shortly before midnight 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.

However a “defiant” Zuma demanded a three month “notice period” before resigning, one ANC official briefed on the conversation said on condition of anonymity.

The ANC may now have to move a no-confidence motion in parliament against its own former leader. This has been described as a “nightmare option” for the party by commentators.

A press conference has been announced at ANC headquarters in Johannesburg at 2pm (midday GMT) on Tuesday.

Zuma’s tumultuous nine years in power have been marred by economic decline and multiple charges of corruption that undermined the image and legitimacy of the party that led South Africans to freedom from apartheid in 1994.

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

The opaque and secretive internal ANC debates and negotiations have provoked much dark humour.

Zapiro, a well-known political cartoonist, drew Zuma and Ramaphosa as gunfighters under a banner bearing the legend “High Noon”, corrected to “High Noonish” then “Low Noon” and finally “Whenever”.