A flurry of videos that were posted on social media and could not be immediately verified purported to show El Helicoide's inmates fleeing their cells and issuing pleas for outside help.
Rep. Mia Love, R-Utah, said she had been speaking with his family and officials from the U.S. Department of State, and had learned Holt was safe.
Chief Prosecutor Tarek William Saab said he sent a commission to the prison to speak with a representative of the inmates.
Richard Blanco, a Venezuelan lawmaker, said on Twitter some were injured during what he said was a rare development at the prison.
Authorities of Venezuela claim that Holt was working with the USA government to overthrow President Nicolás Maduro, a plan they say involved him and his wife stockpiling weapons. "The Venezuelan government is directly responsible for their security and we will hold them responsible if anything happens to them", the embassy tweeted in Spanish.
In the second video, Holt continues by "calling on the people of America" to get him out.
The State Department has been working with USA officials and Sen. "We don't know what to do", Holt says. Marco Rubio talks about him, he won't be released. "They are asking for freedom ... they are asking for health care ... they are asking for human rights. they want the aggression and the torture to stop".
"I need help. So they've taken the entire prison where I'm at".
Holt, of Riverton, has been incarcerated in Venezuela since 2016 after he traveled there to marry his fiance. His trial on weapons charges was scheduled to start Tuesday but Holt and his wife, Thamara Caleno, were never taken to the courthouse by their jailers at El Helicoide, headquarters to Venezuela's feared Sebin intelligence police. His family has said he was in the wrong place at the wrong time of a raid in the Caracas neighborhood where his wife's family lives.
Amid statements of concern by Utah's congressional delegation, Todd Robinson, the top American diplomat in Venezuela, rushed to the foreign ministry to seek information about Holt.
"He remains focused on Josh's safety as we work to bring him home on humanitarian grounds", the office of the Utah Republican said.
His mother, Laurie Holt, confirmed the page belonged to her son.
"It is time for the State Department to quickly produce a plan of action in order to resolve this situation once and for all".