Prominent jailed Venezuelan opposition leader Leopoldo Lopez has announced he has gone on hunger strike demanding "freedom for political prisoners".
In a video leaked from prison, Mr Lopez called for an end to censorship, and for the government to set a date for parliamentary elections.
He also urged Venezuelans to join peaceful marches next Saturday "for peace and democracy".
Mr Lopez is accused of inciting violence during protests last year.
More than 40 people, from both sides of the political divide, were killed in months of protests against the government of Nicolas Maduro.
The authorities say Mr Lopez incited violence and encouraged demonstrators to vandalise government buildings at the end of a protest in February 2014.
He was charged and arrested a few days later.
Mr Lopez said fellow jailed opposition politician Daniel Ceballos was also on hunger strike.
'Crime and corruption'
The video was recorded in Mr Lopez's cell, in the Ramo Verde prison, near Caracas.
Wearing a white shirt and a crucifix, Mr Lopez says the Venezuelan economic crisis has deteriorated since his arrest.
"One year and three months after our call for change, the situation has got even worse. More queues, more inflation, more scarcity, more crime, more corruption," Mr Lopez said.
"We want to call for a demonstration. A strong, massive, peaceful demonstration without any kind of violence in the streets of Venezuela next Saturday.
"Let's go out for peace and democracy. Let's not lose hope, let's not lose faith."
'End of censorship'
The video was uploaded on YouTube and tweeted by his wife, Lilian Tintori.
Shortly before the video was released, Mr Ceballos was transferred from Ramo Verde to a prison away from the Venezuelan capital.
Mr Ceballos is the former mayor of San Cristobal, an opposition stronghold.
"We have three clear demands - freedom for all political prisoners, the end of censorship and repression and that the date for the parliamentary elections is set," Mr Lopez added.
Last month a group of former world leaders sent an open letter to the Venezuelan government expressing its concern "for the difficult social, economic and political situation" in Venezuela.
The group also urged the release of opposition leaders who were jailed for allegedly inciting violence.