Venezuelan President Hugo Chavez is undergoing cancer surgery in Cuba.
Ecuador's President Rafael Correa said his ally is being subjected to a "very delicate operation" Tuesday. President Correa, who spoke in Ecuador, had visited President Chavez in Cuba Monday.
Chavez returned to Cuba Monday for more cancer surgery, after a recurrence of the disease led him to name his vice president as his chosen successor should he be forced from office.
Chavez, who was re-elected in October, acknowledged the seriousness of his situation in a televised address late Saturday. He said Vice President Nicolas Maduro would take over if he is incapacitated, and he urged supporters to vote for Maduro if an election were held.
The South American leader said his Cuban medical team told him it is "absolutely necessary" that he undergo the new operation.
More than 1,000 supporters of the 58-year-old Chavez gathered Sunday in downtown Caracas to show solidarity, while lawmakers unanimously agreed to grant him permission to leave the country for treatment.
While lacking the president's charisma, Maduro is popular among Chavez's supporters because of his close ties to the president. The 50-year-old former bus driver and trade unionist has been foreign minister since 2006 and was named vice president in October.
Chavez, who had just returned from Cuba early Friday, said tests had found a return of "some malignant cells" in the same area where tumors were previously removed. He said his doctors had recommended he have the surgery right away, but that he had told them he wanted to return to Venezuela first.
The socialist leader had undergone operations in Cuba to remove tumors from his pelvic region. He has also had chemotherapy and radiation treatments. The president has never disclosed the type or severity of the cancer.
President Chavez is scheduled to be sworn in for a new six-year term January 10. He has been in office for nearly 14 years, since 1999.