CARACAS (Reuters) - Venezuelan President Hugo Chavez flew to Cuba early on Monday for cancer surgery that he has recognized may end his tumultuous 14-year rule of the South American OPEC nation.

Aides said the 58-year-old socialist leader was optimistic, however, as he left for his fourth operation since mid-2011 for an undisclosed form of cancer in the pelvic area.

"I've just given a heartfelt hug to Commander Chavez in Maiquetia (airport)," said his former vice president, Elias Jaua.

"I told him 'go and come back,'" Jaua added via Twitter. "He said: 'Of course I'll be back, Elias.'"

Information Minister Ernesto Villegas said Chavez's Havana-bound plane had left Caracas at about 1:30 a.m. (0600 GMT).

Chavez stunned Venezuela over the weekend with his announcement that more malignant cells had been found, despite declaring himself completely cured earlier in the year and going on to win a presidential election in October.

In a speech to the nation on Saturday night, he named Vice President and Foreign Minister Nicolas Maduro to take over should he become incapacitated. He also urged supporters to vote for Maduro if there is a new election.

His departure from office, either before or after the scheduled January 10 start of his new term, would trigger a vote within 30 days. It would also mark the end of an era for the Latin American left, depriving it of one of its most acerbic voices and the region's loudest critic of Washington.

Venezuelan global bonds, among the most traded emerging market bonds, rallied on Monday. They had tumbled on Friday, hours after Chavez's surprise pre-dawn return from Cuba, where he had been for medical treatment.

On Monday, the Venezuelan dollar-denominated bond maturing in 2027 rose 1.4 percent in price, putting it on track for its strongest rally since Thursday.

The dollar-denominated bond maturing in 2022 rose 1.7 percent in price, putting it on track for its strongest rally since November 27.

(Reporting by Andrew Cawthorne and Diego Ore in Caracas and Walker Simon in New York; Editing by Lisa Von Ahn)