Venezuelan prosecutors have asked for an arrest warrant to be issued against Edmundo González, the opposition politician widely believed to have beaten President Nicolás Maduro in the recent election, for alleged crimes that could see him spend the rest of his life behind bars if convicted.

González, a 75-year-old retired diplomat, was catapulted into the eye of Venezuela’s political storm earlier this year when he agreed to challenge Maduro in the 28 July presidential election in the place of the banned opposition leader María Corina Machado.

Maduro subsequently claimed victory, without providing proof and in spite of a growing body of evidence suggesting the unpopular authoritarian actually suffered a heavy defeat because of public anger over an economic collapse that has seen millions flee abroad.

Countries including Brazil, Colombia, Mexico have refused to accept Maduro’s claim without the publication of detailed evidence while the EU last week declared the Venezuelan strongman had “no democratic legitimacy as president.”

On Monday evening, the political crisis took another dramatic turn as it emerged that the public prosecutor’s office had asked for González to be arrested for alleged crimes including criminal association, which carries a prison sentence of up to 10 years, and conspiracy, which can be punished with a 16-year sentence.

The signed request, which was published on the public prosecutor’s Instagram account, was made to a judge from a special anti-terrorism court by the prosecutor Luis Ernesto Dueñez Reyes.

Machado, the well-known opposition leader in whose place González ran, denounced the decision, accusing Venezuela’s administration of having “lost all sense of reality”.

“By threatening the president-elect, all they do is unite us further and increase support for Edmundo González among Venezuelans and in the world,” she added on social media, calling for opposition supporters to remain serene.

In an interview with the Guardian on the eve of July’s election, González vowed to build a country of prosperity, democracy and peace if he won the election. Instead, the South American country has been plunged into a moment of profound uncertainty and apprehension.

More than 1,700 people have been detained in the wake of two days of street protests sparked by Maduro’s disputed claim to have won. Maduro has given no hint he is prepared to relinquish power in the lead up to the 10 January inauguration of Venezuela’s next president and has accused Machado and González of being part of a “fascist” foreign plot to topple him.

On Sunday, human rights groups said at least 86 teenagers who were arrested during the government crackdown had been released but hundreds of prisoners have reportedly been taken to high security prisons where they are facing terrorism charges. Several key allies of Machado and González, including one of her closest confidants, the lawyer Perkins Rocha, have been captured by secret police.

González, whom Maduro’s new hard-line interior minister has publicly called a terrorist “rat”, has not been seen in public in recent weeks and his whereabouts is unknown. Machado has also gone into hiding although she has continued to appear at occasional opposition protests.