CARACAS, Venezuela — President Hugo Chavez named his vice president as his chosen successor and was heading back to Cuba on Sunday for more surgery for cancer after announcing that the illness had returned despite two previous operations, chemotherapy and radiation treatment.
Mr. Chavez acknowledged the seriousness of his situation in a televised address Saturday night, saying for the first time that, if he suffers complications, Vice President Nicolas Maduro should take his place as Venezuela's leader and continue his socialist movement.
"There are risks. Who can deny it?" Mr. Chavez said, seated at the presidential palace beside Mr. Maduro and other aides.
"In any circumstance, we should guarantee the advance of the Bolivarian Revolution," Mr. Chavez said.
Several outside medical experts said that based on Mr. Chavez's account of his condition and his treatment so far, they doubt the cancer can be cured.
Mr. Chavez, 58, said he hasn't given up.
"I hope to give you all good news in the coming days," said Mr. Chavez, who held up a crucifix and kissed it. "With the grace of God, we'll come out victorious."
The president, who just returned from Cuba early Friday, said tests had found a return of "some malignant cells" in the same area where tumors previously were removed.
Mr. Chavez, who has yet to be sworn in for his new term after winning re-election Oct. 7, said he would return to Havana on Sunday and would undergo the operation in the coming days.
Mr. Chavez's quick trip home appeared aimed at sending a clear directive to his inner circle that Mr. Maduro is his chosen successor. He called for his allies to pull together, saying: "Unity, unity, unity."
Mr. Chavez said that his doctors had recommended he have the surgery right away, but that he had told them he wanted to return to Venezuela first.
"I want to go there. I need to go to Venezuela," Mr. Chavez recalled telling his doctors. "And what I came for was this," he said, seated below a portrait of independence hero Simon Bolivar, the inspiration of his Bolivarian Revolution movement.
Mr. Chavez had named Mr. Maduro, 50, his longtime foreign minister, as his choice for vice president three days after winning re-election.
Mr. Maduro, a burly former bus driver, has shown unflagging loyalty and has become a leading spokesman for Venezuela's socialist leader in recent years.
The vice president's expression was solemn as Mr. Chavez said that Mr. Maduro should become president if any complication were to prevent him from finishing his current term, which concludes in early January.
Mr. Chavez said that if new elections are held, his movement's candidate should be Mr. Maduro.
"In that scenario, which under the constitution would require presidential elections to be held again, you all elect Nicolas Maduro as president," Mr. Chavez said. "I ask that of you from my heart."
"He's one of the young leaders with the greatest ability to continue, if I'm unable to continue with his firm hand, with his gaze, with his heart of a man of the people," Mr. Chavez said, also saying that Mr. Maduro's leadership and "the international recognition he has earned" make him fit to become president.
Mr. Chavez held a small blue copy of the constitution in his hands and waved it.
The Venezuelan constitution says that if a president-elect dies before taking office, a new election should be held within 30 days and that in the meantime the president of the National Assembly is to be in charge of the government.
While he spoke, Mr. Chavez was flanked by Mr. Maduro and National Assembly President Diosdado Cabello. He asked for lawmakers to grant permission for him to fly to Havana on Sunday. It was unclear what time he would leave.