Chavez says his cancer is back, talks of a successor

"An operation like this, an illness like this, always carries risk," says Hugo Chavez He says his vice president should succeed him if his health worsens Chavez, who won reelection this year, will return to Cuba for the operation

Havana (CNN) -- Venezuelan President Hugo Chavez announced late Saturday that his cancer has returned and that he will go to Cuba to undergo surgery.

Speaking during a televised address from the presidential palace, he said that if his health were to worsen, Vice President Nicolas Maduro should replace him.

It was the first time Chavez spoke publicly about the possibility of a successor -- a shocking admission from a man who looms larger than life in Venezuela and in Latin American politics.

"It's absolutely necessary, absolutely vital that I undergo a new operation," said Chavez.

As he spoke, he repeatedly kissed a cross and at one point broke out into song.

"An operation like this, an illness like this, always carries risk," he said. "If something were to happen that would incapacitate me, Nicholas Maduro should not only finish my term as the constitution requires ... You should also elect Nicholas Maduro to be president."

Just this week, Chavez returned from Cuba after receiving medical treatment. He said doctors detected malignant cells and that he expects to undergo surgery in the coming days.

The president has repeatedly spoken publicly about his cancer battle, but has never specified what type he has.

Chavez, who had surgery in 2011 to remove a cancerous tumor, has undergone further operations and radiation therapy in Cuba since then. He declared himself cancer-free in July.

The government has released few specifics, fueling widespread speculation about his health and political future.

Health rumors dogged Chavez on the campaign trail this year, but didn't stop him from winning reelection in October.

Details of his health, however, have been a closely held secret, and some people who claim to have insider knowledge say the president is in much worse condition than he publicly lets on.