Thousands of pages of US intelligence documents on Nelson Mandela were made public on Wednesday.
They reveal that Washington continued to monitor Mandela as a potential communist menace even after he was released from prison.
The Washington-based group, Property of the People, released the papers to mark the 100th anniversary of Mandela’s birth.
It said it obtained them after years of litigation.
“The documents reveal that, just as it did in the 1950s and 1960s with Martin Luther King jnr and the civil rights movement, the FBI aggressively investigated the US and South African anti-apartheid movements as communist plots imperilling American security,” the group’s president, Ryan Shapiro, said.
“The Mandela Files” can be found at https://propertyofthepeople.org/.