Washington  - US authorities announced Friday the arrests of a retired State Department employee and his wife on charges of spying for the Cuban government.

Authorities allege that Walter Kendall Myers and wife Gwendolyn served as illegal agents to the Cuban government for nearly 30 years and conspired to pass along classified information. Both were arrested on Thursday, the Justice Department said.

"The clandestine activity alleged in the charging documents, which spanned nearly three decades, is incredibly serious and should serve as a waring to any others in the US government who would betray America's trust," Assistant Attorney General David Kris said.

Before retiring in October 2007, Myers worked as a Europe analyst in the State Department's intelligence agency, known as the Bureau of Intelligence and Research.

The arrests followed a three-year investigation by the Federal Bureau of Investigation and the State Department's security outfit. In April an undercover FBI agent posing as a Cuban intelligence officer persuaded the couple to meet with him.

Upon request, the couple agreed to provide information on US officials responsible for Latin America. They also acknowledged receiving encrypted messages via shortwave radio from Cuban intelligence agencies, and travelling abroad to meet with Cuban officials.

If convicted, the charges carry up to 20 years in prison. (dpa)