The National Security Archive over the weekend released documents that show clearly that the CIA, along with Britain’s MI6, were responsible for the overthrow of Iranian Prime Minister Mohammad Mossadeq in 1953. Mossadeq was eventually replaced by the Shah of Iran, who was ousted as leader in the country’s Islamic Revolution in 1979 by Ayatollah Ruhollah Khomeini.

The newly released documents leave in all references to TPAJAX, the secret operation the CIA ran to oust Mossadeq. Previously released documents on the events in Iran blacked out all references to the operation. The documents state clearly that “the military coup that overthrew Mossadeq and his National Front Cabinet was carried out under CIA direction as an act of US foreign policy.”

The Archive, which publishes declassified U.S. government material, said Sunday that “American and British involvement in Mossadeq’s ouster has long been public knowledge, but today’s posting includes what is believed to be the CIA’s first formal acknowledgement that the agency helped to plan and execute the coup.”

A series of now-declassified documents shows that the CIA and Britain’s MI6 were concerned that Mossadeq, who was accused of Communist leanings, would nationalize Iran’s oil industry. Iran, facing labor problems from striking workers and a deteriorating relationship with Britain over nationalization issues, sought help from the U.S. in stabilizing the situation, but was denied by U.S. President Dwight Eisenhower. Six months later, Mossadeq was overthrown.

Because of the nationalistic fervor raised during the deposed leader’s administration, the U.S. and Britain agreed to allow Iran to nationalize the oil industry, but its administration was placed in the hands of the heads of the Western oil companies.

After he was overthrown, Mossadeq was arrested and convicted of treason. He served three years in prison and was released to house arrest, where he died in 1967.