(CNN) Inmates have revolted and taken control of a notorious prison in Venezuela, as the volatile country braces for presidential elections decried as illegitimate by regional leaders.

Men identifying themselves as prisoners posted videos online saying they had taken over a detention center in the Helicoide ("the Helix"), the headquarters of intelligence agency Sebin in the capital, Caracas, because of torture and human rights violations.

The US embassy in Venezuela expressed concern over the incident, after an American political prisoner Joshua Holt, a former Mormon missionary from Utah , posted a video on social media saying he feared for his life.

ALERT If the United States does not promptly rescue Joshua Holt he could be lynched by Maduro's regime agents on next hours. Keep in mind, the rule of law DOES NOT exist in Venezuela... @POTUS @VP @SecPompeo pic.twitter.com/fNAGyGOnmA

Venezuelan authorities later said they had "normalized" the situation at the prison, but inmates refuted the claim.

Venezuelans will head to the polls Sunday to elect a new president as the country is roiled by an economic and social crisis, with millions suffering food and medicine shortages, hyperinflation and growing insecurity.

In a statement released on Monday, representatives from 10 Latin American countries along with Spain and the United States reiterated their "condemnation of the authoritarian regime" of President Nicolas Maduro. The group also issued a final request for the government to suspend the elections.

There have been repeated calls from leaders in the region to suspend the election because it is "illegitimate" and lacking in "credibility."

The Helicoide prison's inmates include jailed opponents of Maduro, as well as US citizen Holt, many of whom have expressed fears over their safety and asked to be freed in postings on social media

"Joshua Holt and other political prisoners are in danger," the embassy tweeted on its verified account . "The Venezuelan government is directly responsible for their safety and we will hold them responsible if anything happens to them."

Estamos muy preocupados por el motín en El Helicoide. Joshua Holt y otros ciudadanos estadounidenses están en peligro. El gobierno de Venezuela es directamente responsable por su seguridad y le haremos responsables si algo les sucede. — US Embassy, VE (@usembassyve) May 16, 2018

Venezuela's Attorney General Tarek Saab later stopped short of claiming the government had regained full control of the detention center in the capital, saying the situation had "normalized".

Speaking to CNN Espanol , Saab said the uprising was "a protest on behalf of the prisoners" and that he had sent a delegation to hold dialogue with the prisoners, which had reached a "positive agreement".

Saab rejected prisoner claims of torture, extortion and minors being held inside the center.

Prisoners, speaking to CNNE, denied that the authorities were in control.

"Inside the prison, all the prisoners are in control. And at that this moment, the people from the government who have approached us have not offered any solutions, none," Daniel Ceballos, a prisoner and former opposition mayor said, adding they were all resisting and asked that for the public to resist alongside them.

Todd Robinson, US Embassy charge d'affaires in Venezuela, told reporters outside the country's foreign ministry Wednesday: "The truth is we don't know anything and it seems like the authorities don't know anything either."