Caracas, Venezuela ? President Hugo Chavez said Thursday his close friend and ally Fidel Castro is in a “great battle for life,” but he also expressed optimism about the 79-year-old Cuban leader’s recovery.

“From here, let’s pray to God for Fidel and his recovery, and he’s fighting a great battle,” Chavez said in a televised speech from the eastern state of Anzoategui.

His statement was the most serious yet from a close Castro ally in describing the 79-year-old Cuban leader’s condition. But Chavez also predicted, with a laugh, that Castro would defy the U.S. government’s plans for a transition in Cuba and emerge from a hospital where he is being treated to reassume the presidency.

Chavez said he had received a message from Castro on Wednesday “that filled me with more optimism, with more faith.”