'Real hell': Venezuelan men allege physical and psychological abuse at CECOT

Mervin Jose Yamarte Fernandez believed he had arrived in Venezuela when he looked out the window of his deportation plane. After he read a sign that said "San Salvador," he heard screams

"We held onto the seats, we didn't want to let go," he told ABC News in Spanish.

Yamarte Fernandez, who was one of more than 250 Venezuelan migrants deported from the U.S. to El Salvador's notorious CECOT prison in March, is one of three Venezuelans who recounted what they say was their experience at CECOT to ABC News.

MORE: Venezuelan migrant files claim over deportation to notorious CECOT prison

The Trump administration invoked the Alien Enemies Act -- an 18th century wartime authority used to remove noncitizens with little-to-no due process -- to deport alleged gang members by arguing that the Venezuelan gang Tren de Aragua is a "hybrid criminal state" that is invading the United States.

The Venezuelans were subsequently released to their home country in a prisoner swap last week.

Yamarte Fernandez and his two countrymen, speaking to ABC News from Venezuela, allege that they were beaten and denied access to lawyers while detained at CECOT. They deny being members of Tren de Aragua.

The alleged beatings began as soon as the Venezuelans arrived in El Salvador, Yamarte Fernandez said. The men, who were in handcuffs and chains, were immediately removed from the plane and taken to CECOT, where they say they were kicked, beaten and shaved.