Hugo Chavez (Creative Commons)

"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 told the BBC.

He subsequently talked of a successor for the first time. He urged supporters to vote for current Vice President Nicholas Maduro if anything happens to him during treatment, according to the Daily Beast.

Maduro, a former bus driver, is one of Chavez's closest advisers. He served as foreign minister and then vice president.

Chavez has been battling cancer since June 2011. In May, he declared himself cancer-free, but there has been speculation since November that the cancer returned.

Reach Senior News Editor Hannah Madans here.