Venezuelan President Hugo Chavez’s closest associates insisted Friday that their leader would continue running the country even as he continues to undergo medical treatment in Cuba after surgery for the removal of a cancerous tumor.

“Chavez is in charge of the Venezuelan government and never was not in charge,” the vice president, Elias Jaua, said on state television. “The president is undergoing treatment and is fully functioning.”

The populist government, built around the persona of a charismatic and omnipresent orator who has ruled for 12 tumultuous years, went to great lengths to convince Venezuelans that Chavez was capable of governing even after undergoing what the president himself called a “major” operation.

But the image many Venezuelans have is not of a leader on the mend but of a thin, pale president who looked vulnerable and emotional as he delivered a 13-minute address Thursday night in which he revealed his condition. The oil-rich country of 29 million is now rife with speculation over whether Chavez will run for a third six-year term in 2012, as he had promised.

“I saw him as depressed. He had to read his speech. These were signs of weakness,” said Margarita Lopez Maya, a political analyst in Caracas, Venezuela’s capital. “They were signs of a Chavez who has been dealt a big blow because he and his followers believed he was a titan.”

Chavez, who turns 57 this month, did not say what kind of tumor was removed, nor did he provide a timetable for his return.

His political foes say that the constitution calls for a transfer of power to the vice president during temporary absences.

“There should be respect for the law,” Maria Corina Machado, an opposition lawmaker, said by phone from Caracas. “The president cannot govern from another country.”

In his address, Chavez said he was aware that his condition had generated anxiety in Venezuela. But he cast himself as connected to the everyday affairs of government.

“I have remained informed and in charge of the actions of the Bolivarian government, in permanent communications with the vice president, Elias Jaua, and my team in government,” he said in his speech.

Talking to reporters in Caracas, Jaua said Chavez would return after he had recovered and that there was no need to transfer power.

“We are absolutely sure that, in spite of the opposition, President Chavez will be here before 180 days,” Jaua told Colombia’s La W radio, responding to a question about whether Chavez could legally govern if he remains in Cuba for more than half a year.

Under Chavez’s orders, the government for nearly three weeks treated his condition as a state secret, with his closest allies issuing contradictory pronouncements. Then came the dramatic speech from Havana, as Chavez told his countrymen that the doctors had carried out a “total extraction” of a tumor.

“I think we have managed it,” he said.

The man who has promised to rule well into the next decade, though, sounded contemplative about his future.

He spoke about God, his mother, the dreams of his followers and darkest chapters in his life, such as the 1992 coup attempt he led as a young army officer and his brief ouster from power in 2002. In both those episodes, Chavez said, he felt that he had been drowning.

Chavez said he went under the scalpel in the early morning hours of June 11 after abdominal pains during a visit with Fidel Castro led him to seek medical assistance. After that operation, Chavez said, “the presence of other formations” was discovered. Examinations confirmed the existence of an “abscessed tumor,” he said, which doctors removed in a second operation.

He spoke warmly about those in Venezuela and beyond who have shown their support for him.

“I don’t in any way want for you to have to accompany me on paths that sink into some abyss,” he said. “I invite you so we can continue to climb new heights.”

Special correspondent Adam Liebendorfer contributed to this report.