By Michael Voss
BBC News, Havana
Two Cuban women, whose husbands are serving long sentences in the United States for conspiracy to commit espionage, are campaigning to be allowed to visit them in jail.
The five are national heroes in Cuba
It is not that the Cuban authorities are refusing them permission to travel but that for some 10 years the American authorities have repeatedly refused to grant them visas.
They are among the wives of the so-called Cuban Five who were arrested in Florida in 1998 as part of an alleged spy ring known as the "Wasp Network".
Earlier this month the BBC broadcast an interview with the group's leader, Gerardo Hernandez, from his prison cell in California.
He is currently serving two life sentences for conspiracy to commit espionage and murder.
It was the first interview with any of the five and made front-page headlines in Cuba, which is adamant that the men were wrongly convicted and has long campaigned for a retrial.
Visits not allowed
From his maximum security penitentiary in California, Gerardo Hernandez described life behind bars.
"The worst part of my treatment has not to do with the prison but the fact I haven't been able to see my wife for the past 10 years because the US government doesn't give her a visa."
I met his wife Adriana at an office in central Havana, a softly spoken yet determined and articulate woman.
She came armed with dozens of pamphlets and books written about the case of the Cuban Five.
I had my laptop with a downloaded copy of the BBC interview plus a transcript in Spanish.
"Seven times I have applied," she told me, "and each time I get a different reason for being refused. I am told I could be a danger to the security of the United States, a possible terrorist or even an illegal immigrant."
Adriana, who does speak regularly to her husband by phone, sat silently as I played the interview, concentrating intensely on her husband's voice, the occasional flash of emotion crossing her face.
"It was like a ray of light," she told me afterwards. "It gives me hope of seeing him face-to-face again. Even though we couldn't touch, just looking into each others eyes would mean so much."
The five Cubans were convicted in a Miami court in 2001 on a range of charges including lying about their identities, trying to obtain US military secrets and spying on Cuban exile groups.
It was a highly controversial trial particularly as it took place in Miami, the centre of anti-Castro Cuban exile activities in the US.
The Miami Herald newspaper recently described it as "one of South Florida's most politically-laden criminal cases."
Of the five, Antonio Guerrero and Ramon Labanino got life, with 19 years for Fernando Gonzalez, and 15 years for Rene Gonzalez.
Gerardo Hernandez was also charged with conspiring in the deaths of four Cuban exiles, whose two light aircraft were shot down by the Cuban air force over the Straits of Florida in 1996.
This is why he is currently serving two consecutive life sentences.
Three of the wives have been allowed to visit their husbands in jail. But Adriana Perez along with Rene Gonzales's wife, Olga Salanueva, have consistently been denied visas to enter the US.
I asked her about the conspiracy to murder charges and the families of the four Cuban exiles who had died in the small planes shot down by the Cuban fighter planes.
"Unfortunately they also had families who have suffered the loss of their love ones. But Gerardo had nothing to do with it," she says.
"That was a decision taken by the Cuban government on the grounds of national defence.
"The government had informed the US that exile groups were repeatedly violating Cuban air space," Adriana Perez told me.
In Cuba the five men are national heroes. There are giant posters of them prominently displayed throughout Havana and across the country.
They are also the focus of regular rallies and demonstrations.
The authorities here say they were not sent to Miami to spy on the United States, but to infiltrate and monitor militant anti-Castro exile groups which the Cubans describe as "terrorists."
The year before their arrest there had been a series of bomb attacks on tourist locations in Havana in which an Italian man died and several Cubans were injured.
The Cuban Five have attracted sympathy from a range of supporters worldwide, with a Free the Five web page being produced in San Francisco.
On 20 August, the 11th Circuit Court of Appeals will hear oral arguments in their case on claims of insufficient evidence.
Adriana Perez and Olga Salanueva are also planning to appeal against the refusal of their visa application, in the hope of being allowed visit their husbands in jail.