Holt, a Mormon missionary from Utah, was jailed in 2016 days after he traveled to Venezuela to marry a woman he met online. Police said he was stockpiling weapons and grenades in public housing.
He has yet to stand trial, and his confinement has become a major point of contention in the already fraught relations between Washington and Caracas.
White House officials on Thursday said Holt was among other U.S. citizens imprisoned at the notorious Helicoide political prison in Caracas, where inmates have overtaken the cell block and demanded release and fair trials.
“The White House holds the Venezuelan government accountable for Josh Holt’s well-being and decries his continued unlawful detention,” the National Security Council said in a statement provided to The Washington Post calling for his immediate and unconditional release.
While the U.S. government has sought to secure Holt's freedom, tensions have spiked ahead of Sunday's presidential election. Autocrat Nicolás Maduro is expected to easily win.
Prisoners rioted and overtook the Helicoide facility over accusations of torture, and videos posted to social media show dozens of inmates roaming freely inside the prison as security forces clad in masks and riot gear secure the exterior of the pyramid-shaped building.
Apparent fears of a brutal crackdown from authorities — or danger in the chaos of the riot — drove Holt to renew his calls for help through two 20-second videos and a Facebook message.
“Help me please United States, how long do I have to suffer unjustly in this place? They want to kill me and paint the walls with my blood,” he wrote Wednesday.
He added, “The sebin has told me that as long as my government continues attacking this government and as long as Marco Rubio continues talking about me the longer that they will never let me go.” Sebin is the acronym for the Bolivarian National Intelligence Service, headquartered at the prison.
A State Department official said the agency has reviewed Holt's videos and called on the Venezuelan government to release him on humanitarian grounds.
The U.S. Embassy in Venezuela offered a stronger response.
“We are very worried about the uprising in the Helicoide [prison]. Joshua Holt and other American citizens are in danger,” the embassy wrote on Twitter in Spanish on Wednesday. “The government of Venezuela is directly responsible for their security and we will hold it responsible if something happens to them.”
Laurie Holt told the Deseret News that her son appeared to be safe as of Wednesday night.
Rep. Mia Love (R-Utah) said Wednesday that she also had received assurances that Holt was out of immediate danger. The lawmaker said she had discussed the issue with Secretary of State Mike Pompeo by phone and had been in contact with the White House.
Olivia Perez-Cubas, a spokeswoman for Sen. Marco Rubio (R-Fla.), declined to comment on how the senator's public remarks may have shaped diplomatic negotiations but said Holt “is an innocent man who is being held as a hostage and should be released immediately.”
Rubio, who has been highly critical of the Venezuelan government, denounced diplomatic back channels between the United States and Venezuela in March, describing them as leverage designed to trade Holt for U.S. concessions over sanctions.
Crisis-ridden Venezuela has 338 political prisoners, according to the legal group Foro Penal, most of whom have been jailed under Maduro.
Maduro is expected to win reelection this weekend despite his sinking popularity and a presidency marked by spiraling inflation, medicine scarcity, crumbling hospitals, rising malnutrition and a massive exodus.
The Helicoide, carved into a central Caracas hillside, was conceived as a modern mall in the 1950s. But it was never finished and was converted to a prison run by the country's intelligence agency, which has been accused of acts of physical and psychological torture.
On Thursday, the inmates demanded the release of all political prisoners in the country and due process for the 265 confined at the Helicoide, according to a count conducted inside and circulated on Instagram by prisoner and activist Lorent Saleh.
Fifty-six prisoners have been held without trial, with more than 100 waiting more than two years for the legal system to address their cases, Saleh wrote.
In another video taken inside the prison and circulated on social media, a more-relaxed-looking Holt explains that he was not taken captive by fellow inmates and said any threat comes from the Venezuelan government.
Diosdado Cabello, a member of the pro-government Constituent Assembly and a senior member of Maduro's government, appeared on state television to denounce Holt and Todd Robinson, the top U.S. diplomat in Caracas.
“Holt is the chief U.S. spy here in Latin America,” Cabello said Wednesday evening. "The U.S. charge d’affairs went yesterday to the Foreign Ministry to put up a show.”
Rachelle Krygier in Caracas contributed to this report.