El Helicoide inmate Daniel Ceballos, a man who was taken as a political prisoner by Maduro in spite of being the elected mayor of the city of San Cristobal, posted a video to social media demanding the presence of government authorities, and denouncing a series of irregularities allegedly taking place inside the prison, including the murder of political prisoners. They say they are doing things but I am still here.
The 26-year-old Holt traveled to Venezuela in 2016 to marry a fellow Mormon he met on the internet. They're outside, they're trying to break in. I am a political prisoner and they won't let me free. I have NEVER done anything wrong in my life. "They're trying to kill me". "They are saying that they want me as their guarantee".
Venezuela's Information Ministry did not respond to a request for comment, but its chief prosecutor said in a tweet that his office was on site, without providing details. "That delegation spoke to a representative of the prisoners to respond to their requests".
Senator Orrin Hatch has been working with the Trump Administration to bring Holt and his wife home. His family has denied the accusations, and believe the Venezuelan government is holding Holt and his wife to bargain with the USA, which has imposed economic sanctions on the country.
The Trump administration has warned that it could put crippling oil sanctions on Venezuela if Maduro goes ahead with what the US and others consider a sham presidential election Sunday.
Several of Mr Maduro's top opponents are barred from running.
Rights groups and Maduro opponents have said several hundred political prisoners were unfairly jailed, while Maduro has said all jailed activists were being held on legitimate charges of violence and subversion.
None of the prisoners' claims could be verified by The Associated Press.
Loud voices outside Holt's cell can be heard in both videos.
In another, a shirtless youth runs down a narrow hallway and knocks out an overhead light with a long stick to shouts of encouragement by other inmates.
Todd Robinson, the charg d'affaires at the USA embassy, went to the Venezuelan Foreign Ministry for information, the embassy tweeted.
"We are concerned about the riot at El Helicoide", Mr Robinson said in a statement, referring to the helix-shaped building where Maduro's top opponents are being held.
"Joshua Holt and other USA citizens are in danger", Robinson said. "The Venezuelan government is directly responsible for its security and we will hold it responsible if something happens to them".