Eight members of Congress have written to the Cuban dictator, Fidel Castro, calling for the immediate release of labor organizers who are serving decades long prison sentences for discussing organizing labor unions independent of the communist government’s official – and only permitted – union.

“The Cuban Revolution, which forcibly brought you to power, was supposed to be based on empowering the disenfranchised and giving power back to the workers who form the backbone of any economy,” the eight congressmen wrote in their letter to Mr. Castro. “Sadly, your actions, specifically the jailing of labor leaders, stand in stark contrast to these principles you claim to support.”

Rep. Vito Fossella, a Republican of Staten Island who signed the letter, said it has special meaning this week because of the Fourth of July celebrations of America’s independence and freedom.

“Just 90 miles from our southern shore is a land that doesn’t get it,” Mr. Fossella, who said he’s been following the plight of the Cuban labor organizers for several years, said. “The Castro regime continues to deny individuals personal freedoms that we cherish here. [In] the year 2006, he still rounds up people who seek to speak their mind.”

The jailed labor organizers are among 75 political prisoners rounded up in 2003 by the regime; most were accused of offenses against the communist government, the chief of staff of Center for a Free Cuba, Felipe Sixto, said.

A spokesman for Amnesty International USA said the human rights organization welcomed the representatives’ letter as a means of publicizing the plight of Cuba’s “prisoners of conscience.”

“I think it’s useful. I think it’s a good thing,” the organization’s advocacy director for the Americas, Eric Olson, said.

Mr. Olson said Amnesty is particularly alarmed that the Castro government has imprisoned the union organizers under harsh conditions for “crimes” that violate international standards, like the freedom to associate.

“Any effort to raise attention to this issue and press the Cuban government on their release is welcome,” Mr. Olson said.

A spokesman for Human Rights Watch said officials of the organization who might be able to discuss the congressmen’s letter were unable to comment because they were traveling abroad.

The imprisoned labor organizers were given sham trials, the pro-democracy Cuban activists say; they are being held in unsanitary cells in separate prisons where they have poor access to water and medical care, and they are frequently the targets of violent attacks by petty criminals that are condoned by prison officials.

In a recent case, one of the political prisoners was stabbed below the belt from behind with a shank. The national secretary for the Cuban Democratic Directorate, Rolando Gutierrez, said he suspects the attack was one of the ones winked at by the warden.

“It happens too often for us to believe this is coincidence,” Mr. Gutierrez said.

The other prisoners include, according to Cuban pro-democracy groups:

* Nelson Molinet Espino, jailed 75 miles from his home at Kilo 8 prison, who was sentenced to 21 years. His daughter is living with her grandparents because his wife is in a hospital.

* Miguel Galban Fernandez, 39, a mechanical engineer, journalist, and labor organizer, who is spending his 26-year sentence in prison with a serious bone condition. He was left disabled because of a car accident. Mr. Fernandez has been on a hunger strike three times since his incarceration.

* Carmelo Diaz Fernandez, 66, who has been sent from his maximum-security cell to the hospital because of ulcers, circulatory complications, and a bone disease. His sentence is 16 years.

* Pedro Pablo Alvarez Ramos, 56, who has lost 44 pounds since he was jailed more than a year ago. He was a top official of the United Workers Council of Cuba before being served with a 25-year prison sentence.

* Ivan Hernandez Carrillo, 33, leader of an opposition party and director of a library, who has been sent to solitary confinement for giving critical reports to international observers about the prison. He was sentenced to 25 years.

* Alfredo Felipe Fuentes, a labor organizer with the United Workers Council of Cuba, who is imprisoned almost 200 miles from his family. His sentence is 26 years.

* Darelys Velasquez Falcon, wife of the imprisoned labor organizer Hector Raul Valle, who has been threatened by the Cuban state police. Ms. Falcon is serving a 12-year prison sentence at Cuba’s own prison at Guantanamo.

Mr. Fossella conceded that the letter alone will probably not encourage Mr. Castro to release the prisoners.

“I mean, listen, history is on the side of Castro thumbing his nose at people who seek personal freedom,” he said. Still, Mr. Fossella said, it’s worth a try.

“Just to lay down and die and not try is not the American way,” he said. “Maybe one day things will click.”

The Cuban mission to the United Nations and the U.S. State Department did not return calls seeking comment.