The opposition boycotted the event, calling it unconstitutional. Henrique Capriles, Maduro's likely opponent in national elections that must be called within 30 days, spoke condescendingly of the former bus driver and union leader, referring to him as "boy" and denouncing him as a "bald-faced liar."
Earlier, Maduro stood before an assemblage of presidents, princes and left-wing glitterati at Chavez's state funeral, his voice booming over the flag-draped casket in a ceremony that at times smacked of a political rally.
"Here we are, Comandante, your men, on their feet!" Maduro shouted, government officials rising behind him. "All your men and women . . . loyal until beyond death."
The funeral began with Venezuela's national youth orchestra singing the national anthem, led by famed conductor Gustavo Dudamel. A government-allied congressman later belted out cowboy songs from Chavez's native Barinas state.
The streets outside the military academy took on a carnival atmosphere, with military bands launching into marches and an expanse of supporters wearing the red of Chavez's socialist party.
Throngs watched the ceremony on huge monitors under the blazing sun, while a line to see Chavez's body stretched 11/2 miles but was halted as the funeral got under way.
In the funeral hall, more than 30 political leaders including Cuba's Raul Castro, Spanish Crown Prince Felipe de Borbon, and Iran's Mahmoud Ahmadinejad stood at attention before Chavez's flag-draped coffin, which was closed for the ceremony.
Maduro said that no Venezuelan leader, even Bolivar, who died in exile, faced and overcame such treachery and opposition as Chavez, who succumbed to cancer on Tuesday, at the age of 58.