CARACAS, Venezuela – Venezuelan President Hugo Chavez was heading back to Cuba on Sunday for a third cancer surgery after naming his vice president as his choice to lead the country if the illness cuts short his presidency.

Chavez's announcement on Saturday night unleashed new uncertainty about the country's future, and his supporters poured into city plazas across the nation to pray for his recovery from what appears to be an aggressive type of cancer.

Some wiped tears, while others held photos of him and chanted in unison: "Ooh-Ah! Chavez isn't going away!"