JOHANNESBURG — Facing increased pressure to resign as South Africa’s leader, President Jacob Zuma clung to power on Wednesday even as his party took steps to formally remove him and replace him with his deputy, Cyril Ramaphosa.

Mr. Zuma’s nine-year presidency, which has been mired in scandals and accusations of widespread corruption in his government, appeared headed to an end over the next couple of days — possibly bringing to a close a prolonged crisis in South Africa and inside the continent’s oldest, most storied liberation party.

In the latest in a series of extraordinary moments for his party, leaders of the African National Congress, which had long steadfastly stood behind Mr. Zuma, said Wednesday that they would move to remove him as president through a vote of no confidence on Thursday afternoon.

Given the party’s dominance in Parliament and cooperation from the opposition, such a motion would almost certainly garner the simple majority needed to pass.