BY LESLEY CLARK

Walter Kendall Myers spent more than two decades deep in the bureaucracy of the U.S. State Department until this week, when federal authorities accused him of a life of intrigue and espionage as a clandestine agent for one of the United States' longtime antagonists: the communist government of Cuba.

The 72-year-old retired State Department employee -- who had enjoyed top-secret security clearance -- and his wife, Gwendolyn Steingraber Myers, 71, appeared in federal court Friday, charged with serving as illegal agents for Cuba for nearly 30 years and conspiring to deliver classified information to its government. They pleaded not guilty.

According to documents unsealed Friday in Washington, Myers, a former analyst on Europe for the State Department, and his bank employee wife agreed in 1979 to deliver U.S. secrets to Cuba.

Federal authorities called the couple's spying for Havana ``incredibly serious.''

Investigators allege Myers -- at the behest of the Cuban Intelligence Service -- landed a job at the State Department, gained sensitive clearance and traveled with his wife to Mexico, the Caribbean, Central and South America, and New York to meet with Cuban agents. He told an undercover FBI source he was so successful he received ''lots of medals'' from the Cuban government, and that he and his wife enjoyed a rare private meeting in 1995 with Fidel Castro.

The couple agreed as recently as April to supply information on the Summit of the Americas in Trinidad and Tobago, the Justice Department said.

The Myerses were arrested Thursday by the FBI and made initial appearances Friday in U.S. District Court for the District of Columbia.

The arrest comes as President Barack Obama has sought to improve relations with Havana. Critics moved swiftly to raise caution flags. Florida Sen. Mel Martinez called on the administration to halt ''any further diplomatic outreach to the regime,'' including the resumption of planned migration talks, ``until the U.S. Congress has a full accounting of the damage these individuals have caused to our national security.''

The Center for a Free Cuba, advocates for dissidents on the island, called on the House and Senate intelligence committees to hold hearings on Cuban intelligence operations in the United States.

The State Department said the arrests were part of a three-year investigation. Secretary of State Hillary Clinton has ordered a ''comprehensive damage assessment'' to determine what may have been divulged to Cuba.

ABOUT THE AGENTS

Court documents portray a couple who relished their work and missed visiting with Cuban intelligence agents when they stopped traveling in 2006 after worries that Myers' boss at the State Department had ``put him on a watch list.''

They proclaimed ''great admiration'' for Ana Belen Montes, a senior intelligence analyst who worked for the Defense Intelligence Agency and was arrested for spying for Cuba in 2001. Montes, Gwendolyn said in the records, ``was not paranoid enough.''

Gwendolyn Myers -- known by the Cubans as Agent 123 and Agent E-634 -- told investigators that her favorite way to pass information along was to swap shopping carts in grocery stores because it was ``easy enough to do.''

The criminal complaint says Kendall Myers -- dubbed Agent 202 -- began working for the State Department in 1977 as a lecturer at the agency's Foreign Service Institute. The government alleges a Cuban official visited him and his wife when they were briefly living in South Dakota after traveling to Cuba in December 1978, and they agreed ''to serve as clandestine agents of the Cuban government.'' They returned to Washington, and Myers resumed working at the State Department.

The indictment says that in 2007 alone -- the year Myers retired from the State Department as a senior analyst for Europe -- he had viewed more than 200 intelligence reports related to Cuba. Of those reports, the affidavit alleges, most were classified ``and marked Secret or Top Secret.''

In court records, the Justice Department said Myers 'expresses a strong affinity towards Cuba and its revolutionary goals and a negative sentiment toward `American imperialism,' '' in a diary he wrote about his 1978 trip to Cuba.

''Fidel has lifted the Cuban people out of the degrading and oppressive conditions which characterized pre-revolutionary Cuba,'' a purported excerpt from his diary reads. ``He is certainly one of the great political leaders of our time.''

Myers surfaced publicly in news reports in 2006, when he criticized U.S.-British relations when it came to the Iraq War.

The affidavit alleges that Cuba often ``communicated

with its clandestine agents in the U.S. through encrypted radio messages from Cuba on shortwave radio,'' and that the Myerses had ``an operable shortwave radio in their apartment of the same make used by Ana Belen Montes.''

Montes is serving a 25-year prison term. The Myerses could face as much as 20 years in prison on at least one charge. The indictment seeks the return of $1.7 million Kendall Myers earned at the State Department and $174,867 in retirement money.

The radios have surfaced in Cuban spy cases dating back nearly two decades. One of the earliest cases unfolded in 1992 when Francisco Avila, a Cuban exile in Miami, revealed on Spanish-language television that he had been a double agent and had received orders from Cuban intelligence officers via shortwave radio.

In 1998, when FBI agents in South Florida shut down one of the biggest Cuban spy rings in U.S. history -- the Wasp Network -- investigators revealed that several of the suspects received coded instructions from Havana via shortwave radio.

WHAT RAISED ALARM

The Justice Department says the Myers espionage began to unravel in April when the FBI began an undercover operation.

The documents say an undercover FBI source, purporting to be a Cuban intelligence officer, approached Kendall Myers in front of the Johns Hopkins School of Advanced International Studies where he was teaching a class, saying he had instructions to contact him and seek out his opinions ``because of the change that is taking place in Cuba and the new administration.''

The couple apparently took the bait, meeting several times with the FBI in various Washington hotel rooms.

They gave mixed reactions to what they thought were the renewed ties to Cuba, saying they were ''delighted to have contact again,'' but were retired and ``don't want to go back into the regular stuff.''

The documents suggest the Myerses' travel to meet with Cuban contacts was ''notable,'' as it began shortly after Montes' arrest in September 2001. Investigators said they believe the Cubans then began meeting their contacts outside the United States because they believed the risk was too great after Montes' arrest.

The Myerses told the FBI source that their last face-to-face contact with Cuban agents was in Mexico in 2005. They said they had kept in touch, via e-mail, with Cuban intelligence sources asking the Myerses to come to Mexico, but they were reluctant to travel. Documents suggest Cuban intelligence e-mails were sent to the Myerses as recently as March.

After the FBI source suggested his next meeting with them would be the last, the documents say, the Myerses admitted to ''mixed feelings'' about giving up their ties to Cuba. ''It's forever,'' Kendall Myers told the FBI source. ``You know, it's like Fidel, it's forever.''

Miami Herald staff writers Alfonso Chardy and Carol Rosenberg contributed to this report.