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.

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.

“You’re going to see real hell,” Yamarte Fernandez said a CECOT officer told him.

The Venezuelan told ABC News that they were forced to change clothes in front of CECOT officers who continued to beat them.

“They wouldn’t let us get dressed,” Yamarte Fernandez said. “If you tried to put on the boxers, they’d hit you with a stick in your private parts. If you screamed, they’d tell you to shut up.”

“We had bruises all over,” he said. “We didn’t know what to do.”

Yamarte Fernandez said he was initially placed in a cell with 10 people but later transferred to a cell with about 80 men.

“We were all cramped together, bumping into each other,” he said.

Similarly, Francisco Garcia Casique told ABC News that he experienced physical and psychological abuse at the prison. He said CECOT officers told the men they would never leave the prison and that “not even the pope or [Venezuelan President Nicholas Maduro] could rescue them.”

At times, Garcia Casique said, he and the other men couldn’t drink water because their bodies had “taken such a beating.” He denies allegations of being a member of Tren de Aragua and said he doesn’t know why he was sent to CECOT.

“They linked me to a gang, but they never showed me any crimes that proved I was a criminal, you know?” Garcia Casique said. “I never thought I would end up in a terrorist prison.”

He told ABC News he worked as a barber in the U.S. and had dreams of supporting his family in Venezuela.

Ysqueibel Penaloza told ABC News he believes the U.S. kidnapped him when he was sent to CECOT and prevented him from making phone calls or seeing a judge.

“It was hit after hit. So much abuse, both physical and psychological,” he said. “They cut our hair when we arrived at the center, they completely humiliated us by making us strip in front of many people to change.”

Penaloza said that when there were visitors, CECOT officers would temporarily give them mattresses, pillows and give them better food.

Last Monday, Penaloza and Yamarte Fernandez said prison officers began to send doctors and nutritionists to check on the Venezuelan men. They say they were given soap, shampoo and toothpaste, and had their hair cut for the first time since they arrived.

On July 18, the men say they were provided clothes and were told by prison officers they were leaving.

“We sang and screamed and we thanked God,” said Yamarte Fernandez.

In a statement to ABC News, DHS Assistant Secretary Tricia McLaughlin said the agency sent the men to CECOT “where they no longer pose a threat to the American people.”

“Tren de Aragua and MS-13 are some of the most violent and ruthless terrorist gangs on planet earth,” said McLaughlin. “They rape, maim, and murder for sport. President Trump and Secretary Noem will not allow criminal gangs to terrorize American citizens.”

DHS didn’t comment on the allegations of abuse.

Penaloza and Garcia Casique told ABC News that they would never return to the U.S.

“They treated me like a criminal, like a terrorist, they tarnished my image,” Garcia Casique said. “They mocked me. I want to be here with my family in my homeland.”

Yamarte Fernandez told ABC News he would return to the U.S. — but not under the Trump administration.

“I have so many dreams and so many things I left behind,” he said. “I am the one who takes care of my family. And the [U.S.] helps you to have everything.”