CARACAS, Venezuela - An aide to Venezuelan leader Hugo Chavez said Monday that there is no doubt the president will run for re-election next year despite his struggle with cancer.

The remark by Finance Minister Jorge Giordani came as Chavez was in Cuba undergoing cancer treatment.

"There's no doubt he's going to be there in the 2012 elections, and afterward for many more years," Giordani said in an interview on state television.

The 56-year-old Chavez, who has been in office more than 12 years, has indicated he intends to continue with his re-election campaign next year despite his illness.

Chavez has not been seen on television since he arrived in Cuba on Saturday night. He said before leaving that he would begin chemotherapy right away.

A message posted on Chavez's Twitter account Monday night said: "Good night fellow citizens! Closing another day of this battle for life here. With unbeatable optimism! Fidel came again!"

Fidel Castro has often been at Chavez's side during the Venezuelan leader's treatment in Cuba.

Chavez underwent surgery in Cuba on June 20 to remove a cancerous tumor, which he has said was the size of a baseball. He hasn't said what type of cancer has been diagnosed or specified where exactly it was located, saying only that it was in his pelvic region.

Chavez has said the chemotherapy is aimed at ensuring cancer cells don't reappear. He hasn't said how long the treatment is likely to last.

When asked how long Chavez could be away, Vice-President Elias Jaua told state television in an interview Monday night: "I don't know. That will depend on his treatment."