President Dilma Rousseff on Friday signed a document creating a panel to investigate human rights violations by Brazil's 1964-1985 military regime.

"It is not a process of vengeance, rather one of construction of the truth and memory, to have a country that is more just, more equal and, mainly, more democratic," she said at the ceremony inaugurating the truth commission.

The seven presidential appointees will have two years to examine abuses committed between 1946 and 1988, encompassing Brazil's two most recent periods of military rule.

The commission's work will not lead to criminal prosecutions, as the Supreme Court upheld last year a 1979 amnesty for both the agents of the 1964-1985 military regime and those who took up arms against the junta, which is thought to have killed around 200 people and tortured thousands more.

The military administration that ruled Brazil from 1945 to 1951 after toppling civilian strongman Getulio Vargas was markedly less repressive.

Rousseff, member of a leftist group that resisted the 1964-1985 junta, said learning the truth about past abuses is fundamental in avoiding a repeat of the murders, torture and political arrests "that stained the history of Brazil."

"The young people who today have a right to freedom need to know that many struggled and died for that precious freedom," the president, who was herself tortured under the junta, said Friday.