Mr. Mugabe said that “we are going to decide a lot” at a special party congress scheduled for December, but added: “I felt I should say it here because I am annoyed.”
Part of the divisions within the party are generational.
Grace Mugabe, 52, leads a faction known as the Generation of 40 — so called because it began with leaders in their 40s; Mr. Mnangagwa, 75, is a veteran of the struggle for independence for Zimbabwe, formerly Southern Rhodesia. Since independence, Mr. Mnangagwa has been a minister in charge of many portfolios, including state security, justice, rural housing and defense.
“This has been building for some time, and the Mnangagwa camp, in trying to fend off the attacks, has made key mistakes and underestimated the strength that Grace Mugabe and her Generation of 40 have been mustering,” said Stephen Chan, professor of world politics at the School of Oriental and African Studies at the University of London. “Relying on his bedrock of military support, it was in the end not enough to prevent President Mugabe from moving against him — almost certainly to allow his wife time and space to build a presidential constituency of her own.”
The next step, Professor Chan said, is to see whether Mr. Mnangagwa is expelled from the party. He retains significant support from the rank and file, so if he leaves the party it could lead to a reduced majority for whoever wins the presidency in 2018.
Rashweat Mkundu, a former director of the Media Institute of Southern Africa, called the move “an end to ZANU-PF as we know it,” with the once-independent party now essentially a vehicle for the president and his family.
“Mugabe will now have to watch for rivals on many fronts, and Zimbabwe’s future is more uncertain with security at higher risk than before,” he said.
Nicknamed the Crocodile because of his own reputation for political ruthlessness, Mr. Mnangagwa had been booted from power before. In 2004, he lost his post as the secretary for administration in the ZANU-PF, after being accused of openly angling for the post of vice president. His rival at the time, Joice Mujuru, became vice president and the favorite to succeed Mr. Mugabe.
But in 2014 Mrs. Mujuru was herself purged, accused of plotting a coup, performing witchcraft and wearing miniskirts, and Mr. Mnangagwa was appointed as her replacement. (Mrs. Mujuru now leads the opposition National People’s Party.)
Whether Mr. Mnangagwa will join with opposition parties — like the Movement for Democratic Change — remains to be seen.
But his allies, many of them fellow fighters from Zimbabwe’s armed struggle for independence, were quick to express outrage.
“We do not care if Mugabe uplifts his wife or not,” said one ally, Victor Matemadanda, the secretary general of the Zimbabwe National Liberation War Veterans Association, expressing the view that Mr. Mugabe’s grip on power has been seriously weakened.