They said they were punished in a dark room called the island, where they were trampled, kicked and forced to kneel for hours.

One man said officers thrust his head into a tank of water to simulate drowning. Another said he was forced to perform oral sex on guards wearing hoods.

They said they were told by officials that they would die in the Salvadoran prison, that the world had forgotten them.

When they could no longer take it, they said, they cut themselves, writing protest messages on sheets in blood.

“‘You are all terrorists,’” Edwin Meléndez, 30, recalled being told by officers who added: “‘Terrorists must be treated like this.’”

From the moment he took office, President Trump has seized on what he calls the threat posed by Venezuela and its autocratic president, Nicolás Maduro, accusing the government and Venezuelan gangs of orchestrating an “invasion” of the United States.

In March and April, the Trump administration made the extraordinary decision to send 252 Venezuelan men to a notorious prison in El Salvador known as the Terrorism Confinement Center, saying they had infiltrated the United States in a form of “irregular warfare.”