The US has strongly condemned this week's arrests

Police have searched the homes of dissidents and journalists across the island, making 72 arrests and seizing computers, typewriters and books.

Two prominent critics of the communist Cuban regime, economist Marta Beatriz Roque and journalist Raul Rivero, are among those detained.

Former United States President Jimmy Carter has implored the government to respect the constitutional rights of its citizens - while urging the US Government to act to deflate "rising tensions" between it and its neighbour.

Human rights in Cuba can ... be viewed as one of the first cases of collateral damage in the second Gulf war. Human rights in other countries could also soon suffer the same fate Robert Menard, secretary-general, Reporters Without Borders (Paris)

The US has expressed outrage at the arrests, calling the round-up an "appalling act of intimidation".

Human rights groups around the world have also condemned the arrests, along with European envoys in Havana, who said the crackdown could damage Cuba's chances of being admitted to a European Union economic assistance programme.

The Cuban authorities accuse their detainees of plotting against Cuba with the top US representative in Havana, James Cason - a charge vehemently denied by Washington.

Ms Roque, who led a hunger strike to demand the release of political prisoners, and Mr Rivero, an independent journalist, are some of the most prominent activists rounded up.

"He is only a man who writes, he is not a politician", Mr Rivero's wife was quoted as saying by the Associated Press.

One report said those detained also included Hector Palacios, a leading organiser of reform efforts known as the Varela Project.

Carter concerns

Mr Carter's worries were expressed through a statement issued by his Carter Center for policy studies.

"I am deeply concerned about reports of detentions of Cuban citizens known for supporting the Varela Project, promoting human rights, and practicing independent journalism," the statement reads.

"I call on the Cuban government to respect [their constitutional] rights and to refrain from detaining or harassing citizens who are expressing their views peacefully.

"I also am troubled by the rising tension between the Cuban government and the US Interests Section in Havana. I urge my own government to work with the Cuban Government to deflate those tensions and establish a relationship of mutual respect."

Last year, Mr Carter made the headlines when he became the first current or former US president to visit Cuba since Fidel Castro came to power in 1959.

Despite making criticisms about human rights violations and the political system, he was allowed to address the Cuban population directly and left on friendly terms.

'Vendetta'

The arrests follow a souring of relations between Washington and Havana, after Mr Cason's arrival as the new head of Cuba's US Interest Section in September.

Mr Cason is currently the focus of something approaching a personal vendetta by the Cuban Government, the BBC's Havana correspondent, Stephen Gibb, says.