She announced in a statement that the party would elect an interim federal leader and interim federal chairperson on November 17. Earlier on Friday, Zille also tweeted this.

"The Democratic Alliance’s (DA) Federal Executive (FedEx) resolved to have a special Federal Council (FedCo) meeting to elect an Interim Federal Leader and Interim Federal Chairperson based on legal advice from the DA Federal Legal Commission (FLC)," reads Zille's statement.

"The election will take place on Sunday, 17 November 2019, at Nkululeko House in Bruma, Johannesburg and will be overseen by the DA Presiding Officer of Federal Council Elections, Desiree Van Der Walt."

Van der Walt also presided over Zille's election last Sunday.

The following day, Johannesburg Mayor Herman Mashaba announced his resignation. Two days later, Mmusi Maimane resigned as leader and Athol Trollip as federal chairperson, effectively rendering the party leaderless.

Under normal circumstances, the federal chairperson would fulfil the functions of the federal leader if he or she had resigned.

Zille said the interim leadership would hold their positions until the Federal Congress was convened – which is provisionally set for April 2020.

"The DA is a resilient party of rules, structures and procedures and looks forward to electing an interim leader through constitutionally sound processes," she said.

"The past two weeks have been a difficult period for the party, and we thank our members, supporters and staff for their continued commitment during this time."

"The DA wishes to assure South Africans that where we govern, we will continue to showcase our unmatched record in delivering services, and where we are in opposition, we will be constructive but firm.

When Maimane announced his resignation on Wednesday, he said: "[T]he DA is not the vehicle best suited to take forward the vision of building One South Africa for All."

In her statement, Zille said otherwise: "The DA remains committed to building One South Africa for All, underpinned by our values of Freedom, Fairness, Opportunity and Diversity."

News24