Havana ? Fidel Castro’s government dealt a crippling blow to Cuba’s opposition movement Monday, sentencing peaceful activists, journalists and an economist to up to 27 years in prison for allegedly collaborating with U.S. diplomats to undermine the socialist state.

Prosecutors sought life sentences for the dissidents, who were among 80 facing closed trials that began Thursday. It was unclear how many dissidents were sentenced Monday.

Opposition political party leader Hector Palacios, among those originally recommended for a life sentence, received 25 years, said his wife, Gisela Delgado.

“This is an injustice,” Delgado said after leaving the courthouse. “We are as Cuban as members of the Communist Party.”

The communist government accuses the dissidents of being on Washington’s payroll and collaborating with U.S. diplomats here to harm Cuba and its economy. In many trials, undercover government agents who infiltrated opposition ranks revealed their true identities to testify against dissidents.

The crackdown ended several years of relative government tolerance for the opposition.

It began when Cuban officials criticized the head of the American mission in Havana, James Cason, for actively supporting the island’s opposition.

“This is an attempt for them to squash down and put the policemen back in the person’s head that many of the Cubans were getting out of their head,” Cason said Monday in a speech at the University of Miami in Coral Gables, Fla.

Cason said journalists were being punished for having such books as “Who Moved My Cheese?” by Spencer Johnson, and others written by Groucho Marx and Stephen King.

“They’re books that they themselves allowed us to bring in for years and years,” Cason said.

Cason denied Cuban government accusations that the U.S. mission had local dissidents on its payroll, saying the mission operates no differently than embassies in other countries.

“Change will come to Cuba. In fact, it is already under way,” Cason said. “Cubans will decide how the Cuba of tomorrow takes shape, and more importantly, the role that each and every Cuban will have in it.”

“We are living a sharp increase in intolerance and persecution, marked by the detentions and summary trials for opponents or dissidents,” read a statement by lay Roman Catholics from the province of Pinar del Rio.

The statement from the Pinar del Rio Diocesan Council of Laymen said the kind of heavy sentences being sought for the dissidents “should never be applied to anyone for thinking or acting peacefully in a different way.”