Thousands of Venezuelans on Monday queued at voting centers around the country to validate their signatures as part of a lengthy process to request a recall referendum.

The oil-rich South American nation is suffering an economic crisis that has led to severe shortages of food, medicines and other basic goods. The dire situation has sparked violent protests and calls for President Nicolas Maduro to step down.

Venezuelan opposition groups leading a campaign to force Maduro from office have collected nearly 1.8 million signatures to formally start the recall process.

The National Electoral Council (CNE) last month rejected a third of those signatures, but later agreed to review others in the next phase of the referendum process.

As part of that step, the CNE has called on those who signed the initial petition to return to polling stations to have their signatures checked and fingerprints scanned.

At least 200,000 signatures must be authenticated by Friday for the process to move to the next stage. After that, the opposition would need to collect 4 million signatures - or 20 percent of the electorate - to officially call the vote.

Time of the essence

The timing of the referendum is important. If Maduro loses a recall vote before the end of the year, the CNE would call a new election. A loss for the president after January 10, 2017, however, would hand power to his socialist vice president until the term ends in 2019.

More than 7.5 million votes in a referendum would need to be cast against Maduro to remove him from office.

Maduro has made it clear he will resist efforts to hold a vote this year, and has threatened to decree emergency measures if confronted with violence. Such measures could prevent the recall referendum from taking place altogether.

Extreme food shortages in early June triggered deadly looting and riots, with at least five people killed and 400 arrested.

The opposition has accused Maduro of mismanaging the economy and trying to drag the recall process out for as long as possible. The president, on the other hand, has challenged the referendum campaign in the Supreme Court, and blames the food crisis on an "economic war" waged by the business elite and Western governments.

nm/cmk (AFP, Reuters, dpa)