The CIA declassified years of Cold War reports Tuesday on its own illegal activities, including details on wiretaps, domestic spying and assassination plots in the years leading up to 1973.

The agency released hundreds of heavily censored documents, known inside the CIA as the "family jewels."

National Security Archive employees work with researchers and analysts on documents released by the CIA on Tuesday.
(Manuel Balce Ceneta/Associated Press)

The documents detail, among other things:

• Assassination plots against foreign leaders such as Cuban President Fidel Castro.
• The testing of mind-altering drugs like LSD on unwitting citizens.
• Wiretapping of U.S. journalists, and spying on civil rights and anti-Vietnam War protesters.
• Opening of mail between the United States, Soviet Union and China — and break-ins at the homes of ex-CIA employees and others.

They include a plan to assassinate Castro in which the Mob was enlisted to try to poison him, but after several unsuccessful attempts to slip pills into the leader's food, the plot was dropped.

Among the several journalists spied on was Jack Anderson, who wrote about CIA plans to kill Castro. His co-worker, Brit Hume, now an anchor on Fox News, was spied on too.

Other reporters' phones were illegally tapped at home and at work in an effort to find out who was leaking classified information to them.

Ottawa was of interest

The CIA also had it sights set on Ottawa, and it is listed as a place of "operational interest" in the agency's efforts to follow draft dodgers or anti-war protesters who could foment further dissent, or what the CIA called extremism, in the U.S.

The documents also offer detail on the Watergate scandal — listing CIA meetings and contacts leading up to the burglary and the disgrace that brought down former U.S. president Richard Nixon.

At one point, the CIA was also testing left-overs from drug companies — drugs that produced what they called "unfavourable side effects" — on army volunteers

The agency wanted to study how people reacted to the drug just in case it was ever used as a weapon on Americans.

James Bamford, who has written several books on intelligence agencies, said it's unusual for an agency to release documents that are this embarrassing.

"It was one compilation of all the bad deeds of the agency from the time it was born in the late [1940s] to basically the mid-70s," he said.

Most of the information has already come out over the years, through the media or through congressional hearings.

James Blanton, director of the National Security Archives, said it would have been silly for the CIA to keep sitting on them.

"You remember what the American astronaut said as he stepped onto the moon — ''A small step for man and giant leap for mankind' — this is a small step for man and a giant leap for the CIA."

With files from the Associated Press