Venezuelan President Hugo Chavez said on Saturday he would undergo another cancer operation in the coming days after doctors in Cuba found a third recurrence of malignant cells in his pelvic area.
The news is a big blow for his supporters in South America's biggest oil exporter, who elected him in October to a new six-year term in power. Chavez has twice said he was cured, and then had to return to Cuba for more surgery.
In a televised broadcast flanked by ministers at the Miraflores presidential palace, Chavez said that if anything happened to him and a new vote had to be held, his supporters should vote for Vice President Nicolas Maduro - the first time the socialist leader has named a successor.
Chavez returned to Venezuela on Friday from having medical treatment in Cuba, ending a three-week absence from public view.
"Unfortunately, during these exhaustive exams they found some malignant cells in the same area ... . It is absolutely necessary, absolutely essential, that I have to undergo a new surgical intervention," the 58-year-old said, looking resolute.
"With God's will, like on the previous occasions, we will come out of this victorious."
The president has already had three cancer operations in Cuba since the middle of last year. News of more surgery will likely raise new doubts about his future and the fate of his self-styled "revolution" in the OPEC nation.
Chavez, who has dominated Venezuelan politics since taking power 14 years ago, said he would return to Havana on Sunday.
Under Venezuela's constitution, an election would have to be held within 30 days if Chavez were to leave office within the first four years of his next term, due to begin on Jan. 10.
The president has been receiving treatment at the Cimeq hospital in Havana as a guest of his friend and political mentor, former Cuban leader Fidel Castro.