Chavez undergoing 'complex' cancer treatment, says VP Jorge Silva / Reuters / REUTERS Venezuelan Vice President Nicolas Maduro (C) and National Assembly President Diosdado Cabello (R) stand next to a painting of Venezuelan President Hugo Chavez as they attend the commemoration of the 21st anniversary of Chavez's attempted cuop d'etat in Caracas, Feb. 4, 2013. By Daniel Wallis and Marianna Parraga, Reuters Venezuelan President Hugo Chavez is undergoing "complex" alternative treatments more than two months after having cancer surgery in Cuba, his vice president said on Wednesday. The 58-year-old socialist leader has not been seen in public since he went to Havana for the operation on Dec. 11, his fourth surgery for cancer in 18 months. Vice President Nicolas Maduro did not give details of the alternative treatments the president was receiving. Chavez has never said what type of cancer he is suffering from, and critics accuse the government of excessive secrecy over his condition. "Today our commander is undergoing alternative treatments ... they are complex and difficult treatments that must, at some point, end the cycle of his illness," Maduro said in comments on state TV. The government, which rejects allegations it has not been transparent about Chavez's health, says he has completed a difficult post-operative period and has started a "new phase" of his recuperation. It has not given details of this new phase. Any new vote in South America's top oil exporter would probably pit Maduro, Chavez's heir apparent, against Henrique Capriles, the 40-year-old governor of Miranda state, who lost to Chavez in last October's presidential election.