JOHANNESBURG — Top leaders of South Africa’s governing party ordered President Jacob Zuma to step down on Tuesday, saying that his continued presence was eroding the “renewed hope” felt since the election of new party leaders in December.

Ace Magashule, secretary general of the African National Congress, said that the party had not given Mr. Zuma a deadline to respond, but added that he was certain that the president would deliver a reply the next day. “Let’s leave it to President Jacob Zuma,” Mr. Magashule said at a news conference at party headquarters in Johannesburg.

The extraordinary confrontation between Mr. Zuma and A.N.C. leaders heightened a power struggle within the party that has governed South Africa since the end of apartheid and has become less known for its heroic past than for widespread corruption and mismanagement. The power struggle has paralyzed South Africa.

In what appeared to be a turning point, the A.N.C., for the first time, moved decisively against the leader it had shielded for the past nine years against a seemingly endless series of accusations of misconduct. But in an indication of what may be the limits of the A.N.C.’s self-inquiry, party leaders stated that Mr. Zuma was being dismissed because he was harming the A.N.C.’s prospects — not because of the ethical issues surrounding him.