JOHANNESBURG, South Africa (CNN) -- South Africa's ruling African National Congress party is to name deputy president Kgalema Motlanthe as the successor to President Thabo Mbeki Monday, two government sources have told CNN.
South African President Thabo Mbeki announced his resignation in a televised address Sunday.
The announcement is expected to be delivered by Mbeki's political rival, ANC President Jacob Zuma -- one day after Mbeki formally announced his resignation.
Motlanthe will take over as South Africa's president until elections in the spring of next year, which Zuma is widely expected to win, the sources said.
South Africa's parliament -- where the ANC holds a two-thirds majority -- will convene Tuesday to consider Mbeki's replacement.
Addressing the nation on Monday, ANC President Jacob Zuma praised his political archrival Mbeki for his work and said he expects a "smooth transition" to a new president, hinting that Mothlanthe would be the party's presidential nominee.
"We have in Cabinet many experienced Ministers including the Deputy President of the ANC, Comrade Kgalema Motlanthe," Zuma said, according to a copy of his prepared statement. "I am convinced that if given that responsibility he would be equal to the task."
Earlier this month, the ANC asked Mbeki to step down after a judge threw out the corruption, fraud and racketeering case against Zuma, calling it invalid and accusing Mbeki's government of political interference in the case.
Critics of Mbeki alleged he pushed for the corruption charges against Zuma.
Mbeki said the African National Congress will determine when his resignation takes effect.
Some of Mbeki's Cabinet told him Sunday that they would quit if he resigned, a source with knowledge of the meeting told CNN, but Mbeki urged them to stay in government.
Mbeki, 66, had been president for nearly 10 years, succeeding Nelson Mandela. "I depart this office knowing that many men and women in South Africa have worked to achieve better lives for all," he said Sunday. Watch the significance of Mbeki "falling on the sword" »
Under his leadership, South Africa has had the longest period of sustained economic growth in its history and has reached out to indigent people in an unprecedented way, Mbeki added.
He said the country still faces economic, corruption and crime challenges. And he gave his vote of confidence to the next leader's administration without naming who that leader would be.
Gwede Mantashe, secretary-general of the African National Congress, announced Saturday that the party -- with which Mbeki has been involved since his teens -- had asked him to leave before his term was up. Mbeki agreed to do so, he said.
Mantashe said the ANC made the decision "for the citizens of South Africa, so there could be stability within the country" and so the ANC movement could remain "stable and unified."
The party's request to Mbeki came after a judge threw out the corruption, fraud and racketeering case against Zuma on September 12, calling them invalid and accusing Mbeki's government of political interference in the case.
The case against Zuma -- who replaced Mbeki as ANC president last year -- was thrown out in September 2006, but the National Prosecuting Authority recharged him. Judge Chris Nicholson made no ruling on Zuma's guilt or innocence, and he could be recharged.
Political observers doubted that would happen because of Zuma's popularity, including with the Communist Party and trade unions.
Zuma has denied the charges. He said the case was politically motivated, and harmed his chances to become the ANC's presidential nominee.
Mbeki recently brokered a power-sharing deal between Zimbabwe's political rivals, who signed the agreement last week in an effort to put aside the violent past and end the crisis that has paralyzed Zimbabwe since disputed national elections in March.