Correctional Services said that “matters are under control” at Johannesburg’s Sun City Prison on Wed.
"It is the movement that shaped them and they in turn shaped the movement. I thank the Sisulu family for giving the whole family up to the struggle for liberation," Mantashe told the audience attending Sisulu's memorial service in Tshwane.
Mantashe evoked giggles from the gathering when he shared quotes from the letters Sisulu wrote to her imprisoned husband, Walter Sisulu.
He said Albertina Sisulu referred to informers as "worms" and wrote to her husband that "the worms have gone so strong that when you plant, the worms destroy the plants instantly".
"This was one of her many novel ways of updating her husband and other detained freedom fighters about the status of the struggle for liberation without catching the attention of prison officials," said Mantashe.
ANC Women's League president and Minister of Basic Education Angie Motshekga said losing a person of Sisulu's standing was an unbearable blow "but the process of healing must begin".
She said Sisulu was a fearless warrior queen from a family of loyal cadres commanding global respect.
"She was a genuine friend for all seasons, a mother, a neighbour and a leader who always led from the front and behind the scenes.
"She dedicated her life to the construction of a democratic state. Her entire life is part of our history," Motshekga said.
The service was attended by Winnie Madikizela-Mandela, Nelson Mandela's wife Graça Machel, former minister in Thabo Mbeki's presidency Essop Pahad and other government ministers and ambassadors.
Sisulu will receive an official state funeral tomorrow. She will be buried alongside her late husband at Croesus Cemetery, Industria.
A night vigil will be held this evening at the Holy Cross Anglican Church in Soweto followed by a valediction to be held at Sisulu's Soweto home on Saturday morning before the funeral service at the Orlando Stadium, Soweto.
Official proceedings are expected to begin at 9am at Orlando Stadium, where President Jacob Zuma is expected to deliver the keynote address.
"There will be 80 buses used to transport family and dignitaries," said Gauteng traffic police spokesperson Obed Sibasa
Dignitaries attending the funeral will travel from Albertina Sisulu Hall in Randburg to Orlando Stadium in Soweto.