Rival rallies set up tense standoff in Venezuela

Tens of thousands of protesters were set to pour onto the streets of Caracas on Saturday to back opposition leader Juan Guaido's calls for early elections as international pressure increased on President Nicolas Maduro to step down.

Major European countries have set a Sunday deadline for Maduro to call snap presidential elections.

Failing that, they will join the United States in recognizing National Assembly speaker Guaido as Venezuela's interim president.

"Maduro's tyranny must end and must end now," US Vice President Mike Pence told a rally of exiled Venezuelans in Miami on the eve of the protest.

Guaido's call for a massive show of popular support coincides with a huge pro-Maduro demonstration.

The ruling Socialist party celebrates the 20th anniversary of the rise to power of Hugo Chavez, Maduro's deceased predecessor, on Saturday.

The "clear goal" of the march was "to accompany the ultimatum given by members of the European Union," Guaido said ahead of the march, which will begin