Venezuelan President Hugo Chavez was in Cuba on Sunday to begin chemotherapy treatment after a cancerous tumor was found and removed recently from his pelvic area.
He was greeted at the airport by Cuban President Raul Castro and Foreign Minister Bruno Rodriguez when he arrived late Saturday.
"It is not time for dying; it's time to live," Chavez said in Caracas before his departure, according to an AFP journalist. "I am going for a few days but I am not saying goodbye ... I will return better."
The 56-year-old president gave a televised speech shortly before leaving Caracas, saying, "I have to say I am optimistic. I have never loved life the way I am loving it now."
He said that since the removal of a tumor "right up to this very day, no other cancerous cell has been detected in my body." It was a rare disclosure on an illness his critics complained the president kept too close to the vest.
Chavez, who was accompanied by his daughter Rosa, was given a sendoff at the airport by most of his state ministers. The length of his stay in Cuba is not known.
On Friday, Chavez asked the National Assembly for permission to travel to Cuba to continue treatment after his June 20 operation in Havana.
"I will travel to Havana to begin what we have called the second stage of this slow and complex process of recovery, which is going well," Chavez said.
Though the National Assembly unanimously approved his travel request, which is needed for the president to leave the country for more than five days, opposition leaders say it is unconstitutional for Chavez to continue to exercise executive authority from Cuba.
"When the president leaves the country, the vice president must assume the chief executive role. It is their duty," said opposition lawmaker Hiram Gaviria.
The president said he would hand over his full presidential powers to Vice President Elias Jaua only "if I felt my abilities were impaired." Chavez did issue a decree giving Jaua and Finance Minister Jorge Giordani a few administrative and economic powers.
Chavez, in power since 1999, is his party's candidate for the 2012 presidential election, where he will be seeking a third six-year term in office. On Saturday his supporters accused political foes of encouraging a coup.
Critics of the president have demanded details of his cancer as well as answers to why he cannot be treated in Venezuela, where authorities say they have created a quality health care system.
Cuba, the America's only one-party communist regime, is Chavez's closest regional ally.