Caracas (AFP) - Venezuelan President Nicolas Maduro vowed to jail opposition leaders if they incite violence during upcoming protests seeking a referendum on removing him from power.
Maduro, blamed by opponents for a devastating economic crisis, accused opposition leaders of plotting a "terrorist coup" against him before Thursday's nationwide protests.
"We must defeat the coup d'etat without impunity," he told supporters at a rally in Caracas billed as an early counter-demonstration.
"Whoever gets involved in a coup plot, or calls for violence, is going to jail, sir. Shriek, weep or scream, but you're going to jail."
Maduro accused the United States of plotting against leftist governments in Latin America.
"The threat is coming directly from American imperialism," he said.
One opposition figure, Yon Goicoechea, was arrested on charges of possessing explosives which he allegedly planned to detonate at the upcoming protests.
Opposition lawmaker Tomas Guanipa said the authorities had planted evidence against him.
"Even if you throw us all in jail, you won't stop the people from taking to the streets to fight for democratic, electoral and peaceful change," he said.
The protests are the first since electoral authorities indicated it was too late to organize a recall vote this year -- infuriating the opposition, which wants a referendum by January in order to trigger new elections.
The protests are intended to pressure authorities to let the referendum go ahead.
Venezuela is facing a deep economic recession fueled by the fall in the price of oil, its main export.
With shortages of food, medicine and basic goods, the opposition coalition behind the referendum drive -- the Democratic Unity Roundtable (MUD) -- insists that ditching Maduro's socialist government is the only way out of the crisis.
Venezuela's neighbors are becoming increasingly wary of developments in the once-booming economy.
The Organization of American States (OAS) on Tuesday denounced Maduro's government as a "dictatorship," criticizing its "wave of repression" against opponents before the march.
The measures "completely contradict democratic principles and values," OAS chief Luis Almagro said, calling on the government to permit the demonstration as part of a "broader framework of freedom."
Venezuela's Catholic Church also called on the government to allow Thursday's protests to go ahead freely.
The journalists' union meanwhile said conditions for the press are difficult ahead of the demos.
Masked attackers threw Molotov cocktails and flaming excrement at the offices of the opposition-leaning newspaper El Nacional on Tuesday, after the authorities denied entry on Monday to a team of reporters from Al Jazeera TV.