Venezuelan opposition leader Maria Corina Machado has addressed a mass rally in the capital Caracas, defying government calls for her arrest.
Ms Machado went into hiding earlier this week after accusing President Nicolás Maduro of defrauding the opposition candidate, Edmundo Gonzalez, of a clear victory in the presidential election.
The president in turn has accused Ms Machado of stocking violence and said she and Mr Gonzalez should face decades behind bars.
The electoral commission – controlled by allies of Mr Maduro – has insisted he won with 52% of last Sunday’s vote, but independent observers have said it lacked transparency.
The commission has not published the full breakdown of results. The opposition has said its own vote tally shows it won the election by a wide margin. Opinion polls ahead of the election had suggested a clear victory for the challenger.
On Saturday Ms Machado addressed thousands of her supporters in Caracas from a truck bearing a banner reading “Venezuela has won”.
“We have never been so strong as today,” she told the crowd, adding that “the regime has never been weaker… It has lost all legitimacy”.
The opposition leader, who was blocked from running in the election, has spent days in hiding.
Earlier this week, Ms Machado wrote in The Wall Street Journal that she had been left “fearing for my life,” along with other opposition leaders.
She was greeted by cheers of “freedom, freedom” and was accompanied by several other opposition leaders – but not Mr Gonzales.
In a separate a video message he urged supporters to “respond to the regime’s attacks with hope, harmony, and peace”.
Security forces in Venezuela have spent the past several days trying to contain mass protests. At least 11 people have died in clashes with police.
More than 1,000 opposition demonstrators have been arrested.
The government is coming under increasing international pressure. US Secretary of State Antony Blinken said on Friday that there was “overwhelming evidence” that Mr Gonzalez had won the election.
His intervention comes as the presidents of Brazil, Mexico and Colombia all called on Venezuela to release detailed election results.
Other regional governments, including Argentine, Costa Rica, Panama and Uruguay have all raised concern over the vote.
But Mr Maduro has been backed by his allies in Russia, China and Cuba.
He has asked Venezuela’s top court to audit the voting tallies with a view to confirming the results, which handed him another six-year term in power.
The opposition says the court is in the hands of government loyalists who will delay the publication of the tallies. Mr Gonzalez boycotted court proceedings on Friday.