President Hugo Chavez of Venezuela will return to Cuba on Sunday for more cancer surgery and has spoken openly for the first time of a successor.
In a televised address to the nation, he named Vice-President Nicolas Maduro as the man to replace him if anything should happen to him.
Mr Chavez returned from cancer-related treatment in Cuba on Friday.
He said thorough tests undertaken during his stay had detected more cancerous cells.
"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," he said.
"With God's will, like on the previous occasions, we will come out of this victorious."
Mr Chavez said his doctors had recommend he stay in Cuba and undergo surgery this weekend, but he told them he wanted to return to Venezuela first.
The BBC reports Mr Chavez underwent surgery for an unspecified type of cancer in the pelvic region after a diagnosis in June 2011, and had another bout of surgery last February along with chemotherapy and radiation treatments.
He declared himself free of cancer in May. He was re-elected in October for a fourth term in office, but acknowledged that the campaigning had left him exhausted and in some pain.
Mr Maduro, a former bus driver, is one of the president's closest advisers. He was foreign minister since 2006 until he was chosen by Mr Chavez to be vice-president in October.
Mr Chavez is due to begin his new six-year term in office on 10 January.
The constitution states that should the president leave office in the first four years of his term then an election must be held within 30 days.
