President-elect Donald Trump says Venezuela's embattled opposition leader must be protected as President Nicolas Maduro takes the oath of office for a third six-year term.

Venezuela opposition leader María Corina Machado's aides said she was detained Thursday, followed moments later by official denials of her arrest, in a confusing episode that capped a day of protests seeking to block President Nicolás Maduro from clinging to power.

It is not viable for Venezuelan opposition leader Edmundo Gonzalez to enter the country, his ally Maria Corina Machado said on Friday, shortly after President Nicolas Maduro was sworn in for a third term despite months of controversy over the country's contested July election.