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.

Maria Corina Machado, a 57-year-old engineer with rock-star appeal, became the fearless figurehead of Venezuela's opposition after being barred from challenging strongman Nicolas Maduro in elections last July.

Machado’s appearance at the rally was her first public appearance in months, since a government crackdown on Venezeulan opposition figures and their supporters last year.