Aldrich Ames, a CIA officer who became one of America's most damaging double agents, has died aged 84.
The former counterintelligence officer, who was serving a life sentence without the possibility of parole, died on Monday at the Federal Correctional Institution in Cumberland, Maryland, CBS News, the BBC's media partner in the US, reported.
Ames was jailed on 28 April 1994 after he admitted to selling secret information to the Soviet Union and later Russia.
He compromised more than 100 clandestine operations and divulged the identities of more than 30 agents spying for the West - leading to the deaths of at least 10 CIA intelligence assets.
Seeking money to pay debts, Ames said he began providing the KGB with the names of CIA spies in April 1985, receiving an initial payment of $50,000.
Known to the KGB by his code name, Kolokol (The Bell), Ames went on to identify virtually all of the CIA's spies in the Soviet Union, for which he was well rewarded.
Ames's treachery, driven by escalating personal debts, led to one of the most significant intelligence breaches in U.S. history. His actions not only destroyed lives but also severely compromised U.S. intelligence operations.
Throughout his career, Ames's issues with alcohol and security violations were overlooked until his espionage activities set off a mole hunt that ultimately led to his arrest.
