Praise from Castro for couple who 'passed on US secrets for 30 years'

Intelligence official and wife 'motivated by anger at US foreign policy'

He is said to have been the subject of some cartoonish plots over the years, from poisoned ice cream, mines disguised as sea shells and, of course, exploding cigars, but even Fidel Castro says that the story of an elderly American couple accused of spying for Cuba for three decades reads like "an espionage comic strip".

The retired Communist leader declined over the weekend to say whether Walter Kendall Myers, 72, a US intelligence official, and his 71-year-old wife Gwendolyn really had passed secrets to his regime, but he said they deserved praise if they did.

"I can't help but admire their disinterested and courageous conduct on behalf of Cuba," he wrote in a web column published three days after the couple's sensational arrest.

"Those who in one form or another have helped to protect the Cuban people from the terrorist plans and assassination plots organised by various US administrations have done so at the initiative of their own conscience and are deserving, in my judgment, of all the honours in the world."

As the US State Department works to assess the security damage that may have resulted from the couple's alleged subversive activities, details are emerging about the anger the pair felt at US foreign and domestic policies during the Seventies, when they are said to have begun working for Cuba.

Their friends and colleagues have expressed their shock at the charges unsealed by the US authorities last week. Larry MacDonald, who lives at the marina in Maryland where the couple docked their 38ft boat, told the Washington Post that they were admired for their intelligence and graciousness. "When I heard they were arrested, I felt like they had arrested Santa Claus and the Easter Bunny."

The couple are alleged to have received encrypted radio messages in Morse code on a short-wave radio, and passed copies of documents to Cuban agents in public locations like supermarkets. The indictment alleged that Mr Myers sometimes took documents from the State Department home and hid them in books. His top secret security clearance, given in 1985 and upgraded in 1999, gave him daily access to classified information until his retirement in October 2007.

Hillary Clinton, the US Secretary of State, ordered a damage assessment of what the couple may have revealed to the Cuban authorities. In particular, the department is concerned that Mr Myers did not stop at revealing details about the CIA's activities in Cuba but may also have passed on information about their activities in Russia, China and elsewhere.

As an adjunct professor of Johns Hopkins University, Mr Myers could also have passed on details of students likely to end up working for the CIA.

He was a professor of international relations, particularly of British politics, and a critic of Tony Blair's government. In the final months of his State Department career, he caused an international storm by claiming there was no "special relationship" between Britain and the US and that he felt "ashamed" of the way Tony Blair had been treated, winning nothing in return for his support for the war in Iraq.

Mr Myers was a 41-year-old contractor working as a teacher at the State Department's Foreign Service Institute when he first traveled to Cuba in December 1978.

"I have become so bitter these past few months. Watching the evening news is a radicalizing experience," he wrote in a diary entry from the trip, released in court documents. Castro's Cuba, by contrast, was "so exciting" and the revolution had "released enormous potential and liberated the Cuban spirit".

The couple are due in court for a bail hearing on Wednesday. They have pleaded not guilty to conspiracy, fraud and being agents of a foreign government.