With his illness reappearing and his future in doubt, Venezuelan President Hugo Chavez underwent surgery Tuesday to try and keep his cancer at bay.

Doctors in Cuba began Chavez’s fourth cancer-related surgery after tests showed that "some malignant cells" had reappeared in the same area in his pelvic region where tumors were previously removed.

Ecuadorean President Rafael Correa called it "a very delicate operation."

Information Minister Ernesto Villegas, reading a government statement on Venezuelan television, said the surgery is under way and Chavez has "absolute confidence he will overcome the obstacles that have emerged in the path of life."

It is the fourth operation that Chavez has undergone since June 2011.

"His medical team has transmitted its optimism about the success of this operation," the government said in an earlier statement.

"He's passing through one of the hardest moments of his life. Our heart and our solidarity are with a historic president," Correa said at an event in the Ecuadorean city of Tulcan.

Correa, a close ally of the socialist leader, traveled to Cuba on Monday to meet with Chavez.

Uncertainty rules across Venezuela  after Chávez's relapse.

Underlining the gravity of the situation, Vice President Nicolás Maduro broke into tears on Monday at a political rally hours after Chávez flew to Havana.

"Chávez has a nation, he has all of us, and he'll have all of us forever in this battle," said Maduro, who wiped away tears while speaking to supporters. "Even beyond this life, we're going to be loyal to Hugo Chávez."

Chávez said for the first time on Saturday that if he suffers complications, Maduro should take over for him and should be elected president to continue his socialist movement.

Before leaving for Havana early Monday, Chávez met with military commanders at the presidential palace and promoted his defense minister, Diego Molero, to the rank of admiral in chief. Chávez showed Molero and other military commanders a golden sword that once belonged to independence hero Simon Bolivar.

Holding the sword, Chávez told the officers that he fully trusts them. He also warned of potential conspiracies by enemies, both foreign and domestic.

"I'm totally sure that our homeland is safe," Chávez told them. He urged them "not to give in to intrigue."

Based on reporting by The Associated Press.

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