WASHINGTON — An ex-career diplomat who once served as US ambassador to Bolivia has been sentenced to 15 years in prison for working as an agent for Cuba.

Victor Manuel Rocha, 73, secretly passed information to the Cuban government for more than 40 years, according to prosecutors.

In February, Rocha changed his initial not guilty plea in a Miami court and ensured he would avoid a trial. The espionage case is among the highest profile ever between the US and Cuba.

Dressed in a beige jail uniform on Friday, Rocha told a federal courtroom in Miami: "I plead guilty."

In addition to prison, Rocha must also pay a $500,000 fine and cooperate with authorities.

US Attorney General Merrick Garland referred to Rocha's crimes as "one of the highest-reaching and longest-lasting infiltrations of the US government by a foreign agent".

The Colombian-born, Yale and Harvard-educated Rocha served as US ambassador to Bolivia between 1999 and 2022, as well as in a variety of other diplomatic postings in Argentina, Honduras, Mexico and the Dominican Republic.

He also served in other government roles, including one with the National Security Council.

After his diplomatic service ended, Rocha served as a consultant for the US military's Southern Command, which oversees all of Latin America and the Caribbean — including communist Cuba.

In November 2022, an undercover FBI agent contacted Rocha on WhatsApp and claimed to be working on behalf of Cuba's intelligence service.

The agent said he was delivering a message from "your friends in Havana", according to court documents.

Over the course of three subsequent meetings, Rocha revealed details of his previous espionage on Cuba's behalf.

At one point, Rocha used the term "we" to describe Cuba and himself, vowing to "protect" what "we" have done together.

When asked whether he was "still with us", Rocha told the undercover agent that he was "angry" that his loyalty to the Cuban regime was being questioned. "It's like questioning my manhood," he said.

The US has had a tense relationship with Cuba ever since Fidel Castro overthrew the island's US-backed government in 1959, a revolution that was swiftly followed by a US trade embargo.

While then-president Barack Obama and former Cuban President Raul Castro took steps to normalize relations in 2015, many of those actions were reversed by the Trump administration.

In an interview with the BBC, former CIA counter-intelligence chief James Olson said the case was emblematic of how Cuba's intelligence service "beat" their US adversaries over the decades.

"They owned us," Olson said. "That's one of the reasons I have this personal grudge against the Cuban intelligence service because they have been so successful in operating against us."

Olson referred to Rocha as a "traitor".

"He betrayed our country," he said. "I think that's contemptible, and I don't think he's going to see the light of day again." — BBC