Venezuelans queued to get fingerprinted in a crucial phase of efforts to force president Nicolas Maduro from power, after food shortages sparked deadly protests and looting. Thousands of Mr. Maduro’s opponents lined up yesterday to submit their fingerprints so Electoral Authorities can authenticate signatures on a petition calling for a referendum on his rule.

The procedures, due to run until Friday, could make or break the bid to hold a recall vote on President Maduro. The opposition says he must be removed to rescue the South American country from economic disaster. Crowds of citizens holding identity cards queued up to have their electronic prints taken at the National Electoral Council in Caracas and around the country.

Of the 1.3 million signatures recorded by the Electoral Board in the initial petition, at least 200,000 must be authenticated to pass to the next phase. The next step will require the collection of four million more signatures to call a full referendum. Venezuela is grappling with an economic crisis sparked by the plunge in prices for its crucial oil exports.

People face shortages of basic foods and goods as well as electricity blackouts. The opposition says President Maduro’s economic management is also to blame. They denounce the jailing of his political opponents. The president is resisting efforts for a referendum. He has alleged irregularities in the signature process. The country’s food crisis erupted into deadly looting last week. Authorities said at least five people were killed and more than 400 arrested. The president has warned he may decree emergency measures if confronted with more violence.