Zimbabwe opposition leader Morgan Tsvangirai has named Nelson Chamisa the acting president of the Movement for Democratic Change with immediate effect.
The party said that Chamisa, one of three party vice presidents, will serve as president until Tsvangirai returns from receiving cancer treatment in neighboring South Africa. The party said the party's two other vice presidents also are in South Africa.
The 65-year-old MDC leader has been in and out of the hospital since revealing last June that he has colon cancer.
Over the past few days there have been unconfirmed reports that Tsvangirai is gravely ill and might not survive, but Tsvangirai has disputed that on his Twitter feed. "Of course I have cancer and not feeling too well but I am stable and the process is under control," he wrote.
Tsvangirai formed the MDC in 1999 to challenge President Robert Mugabe, who was forced out of office in November when a military uprising ended his 37-year hold on power.
The question of Tsvangirai's successor has come up over in the past year, with support divided among Chamisa and the other vice presidents, Thokozani Khupe and Elias Mudzuri. It is not clear how the party will settle the succession issue should Tsvangirai leave his position.
(VOA Zimbabwe Service contributed to this story.)