The 56-year-old socialist leader was sworn in at the Supreme Court before an audience of hundreds, rather than the sidelined, opposition-controlled National Assembly, before heading to a ceremony at Venezuela’s military academy.
Maduro’s new mandate will keep him at the helm of the oil-rich, cash-strapped country until at least 2025.
The opposition called for protests during the ceremony, while thousands of pro-Maduro flooded the streets.
“There were thousands and thousands of people that came here to show their support for President Nicolas Maduro, saying that they support Hugo Chavez’s socialist revolution. They’re also saying that any changes that happen in this country need to happen with the revolution and with the current administration,” said Al Jazeera’s Teresa Bo, reporting from Caracas.
Several countries have said they will not recognise Maduro’s new mandate.
With the exception of Mexico, the Lima Group – made up of 14 Latin American countries and Canada – has urged Maduro to cede power to the National Assembly until new elections can be held.