President Hugo Chavez\'s medical team expressed \"optimism\" as the cancer-stricken Venezuelan president underwent a fourth round of surgery in Cuba on Tuesday. In a statement broadcast on TV and radio, Communications Minister Ernesto Villegas said the team had begun operating on the 58-year-old Chavez, who traveled to Havana on Monday after revealing that his cancer had returned. \"The medical team has transmitted its optimism about the success of this operation, which is part of the treatment plan that commandante Hugo Chavez is following to recover his health,\" Villegas said earlier. Ecuadoran President Rafael Correa, who visited Chavez on Monday, described it as \"a very delicate operation.\" \"He is going through one of the most difficult moments of his life, this dear friend, colleague and Latin American leader, commandante Chavez,\" Correa said in the border town of Tulcan, Ecuador. \"Truly, he is a historic president and let\'s hope he comes through this health problem totally reestablished,\" said Correa, who was meeting with Colombia\'s President Juan Manuel Santos. Chavez flew to Havana for his fourth round of surgery after revealing to his stunned countrymen Saturday that his cancer had returned just two months after his triumphant re-election to a six-year term. Chavez, who was first diagnosed with the disease in June 2011, had assured Venezuelans that he was cancer free after three surgeries and debilitating rounds of chemo and radiation therapy. Significant aspects of his condition -- including the type, location and severity of his cancer -- have been kept secret over the past 18 months, fueling rumors and uncertainty about Venezuela\'s future. Chavez made clear before his departure to Havana that he was facing a serious setback, publicly naming Vice President Nicolas Maduro as his preferred successor for the first time. Without formally handing over the presidency, Chavez said he was delegating the country\'s \"high political command\" to Maduro while he was gone and said the vice president would succeed him if he became incapacitated. Under Venezuela\'s constitution, elections must be held within 30 days if the president dies or is incapacitated either before being sworn into office or in the first four years of his term. Correa, a firebrand leftist economist who could succeed Chavez as leader of the Latin American left, on Monday flew to the Venezuelan\'s side in Havana where he found him in \"great spirits.\" \"He gives us all strength,\" Correa said on Twitter, upon his return to Quito. Correa said he had also visited Cuban President Raul Castro and his predecessor Fidel Castro during his day-long stay in the Cuban capital. With Cuba\'s backing, Chavez has taken the lead in forming a bloc of leftist Latin American governments that vehemently opposes the United States and has friendly relations with US adversaries like Iran. Members of the group include Ecuador, Nicaragua, Bolivia, Venezuela and Cuba. Though Cuban authorities did not announce it, Chavez is believed to be receiving treatment at the same Havana hospital he was at earlier, known as CIMEQ. The hospital, where Fidel Castro has been cared for, is seen as the communist country\'s best facility for complicated medical conditions.