South Africa's former President Jacob Zuma has been suspended from the party he once led, after refusing to vote for it and launching a rival organisation.
The governing African National Congress (ANC) announced its decision on Monday.
"Zuma and others whose conduct is in conflict with our values and principles, will find themselves outside the African National Congress," said Secretary-General Fikile Mbalula.
Mr Zuma's nine years as president, from 2009, were dogged by scandal.
An official inquiry said the former president placed the interests of corrupt associates ahead of those of his country, in a process known as "state capture". After he left office, he was jailed in 2021 for not appearing at the inquiry.
He also faces corruption charges over a 1999 arms deal. He denies wrongdoing in all cases.
Despite these issues, the ANC had tolerated Mr Zuma, but the creation of a new party that may pose a threat was deemed a step too far.
The party, uMkhonto we Sizwe (MK), meaning "spear of the nation", shares a name with the ANC's former armed wing he once served in.
In a scathing letter, Mr Zuma's former ANC bedfellows accuse him of debasing the "proud history of armed struggle against the apartheid regime" through the "opportunistic use of military symbolism".
They also say MK only exists to "erode the support base of the ANC".
South Africa's current President, Cyril Ramaphosa, replaced then-President Zuma in 2018 and promised to clean up government. He now leads an embattled ANC into this year's general election.
'Rescue' mission
At MK's official launch in December, a statement was read on Mr Zuma's behalf saying he would "die a member of the ANC" but not vote for it, adding that some of its leaders behave in an "un-ANC manner" and it was now his mission to "rescue" the "once-great movement".
Mr Zuma has also launched highly personal attacks on his successor, and former deputy, Mr Ramaphosa.
The BBC's Daniel de Simone in Johannesburg says many South Africans see Mr Zuma as representing what is wrong with the recent past, and as having tainted the ANC.
Yet he commands huge loyalty from some quarters. Thousands of South Africans rioted in protest at his 2021 jailing for contempt of court, and a recent poll estimates that almost one in three South Africans approve of him.
It is not yet clear how far this will translate into popular support for his new MK party at the ballot box, but it is likely to cost the ANC votes.
The ANC, which had its roots in the liberation struggle against apartheid, has governed South Africa ever since white-minority rule ended in 1994.
Mr Zuma, 81, had been a lifelong member of the ANC.
He joined aged 17 with no formal schooling and soon rose through the ranks of the ANC's military and intelligence wings, followed by top posts in his home province of KwaZulu-Natal and ultimately the deputy presidency and presidency.
Correspondents say this year's election is viewed by many as the most competitive since the ANC came to power in 1994.
BBC