"I finished the first round of chemotherapy I started a few days ago," Chavez told state television VTV by telephone. "This round ended successfully."

The 56-year-old underwent an operation in Cuba a month ago for a cancerous tumour in his pelvic area. He returned to Venezuela, then went back to Havana on Saturday for a so far undetermined period in order to undergo additional chemo treatments.

"Today, we are preparing for the second round," Chavez added. "There will be several rounds in order to win this battle and eliminate all risk of malignant cells."

He vowed "unsurpassable" courage in his battle against the cancer.

Few details have been provided about the firebrand leftist leader's illness, and much uncertainty surrounds the upcoming 2012 elections, in which Chavez has vowed to run.

Copyright APP (Associated Press of Pakistan), 2011

Copyright AFP (Agence France-Presse), 2011