A truth commission on Wednesday urged Brazil to scrap an amnesty for torturers, in a final report on the 1964-1985 military dictatorship that says at least 434 people were killed or disappeared by the regime.

The panel made its recommendation to President Dilma Rousseff, herself a victim of torture during the dictatorship.

"We respect and revere all those who fought for democracy," said Rousseff, struggling to maintain her composure during an emotional speech in which she said today's generation and the victims' families deserved to know the truth.

Otherwise, she said, "they will continue to suffer as if their families were dying anew."

Unlike its South American neighbors, Brazil has not prosecuted military officials for regime-era crimes, because of a 1979 amnesty law, ratified in 2010, preventing it from doing so.

A law signed by Rousseff three years ago created the truth commission, which is empowered to summon witnesses under oath but not to bring any prosecutions.

Wednesday, the group urged the amnesty be lifted for torturers and those who had willfully violated human rights, adding that the final tally of victims likely is an undercount.

"These numbers do not correspond to the total of dead and disappeared," a commission statement read.

"These are only the cases it was possible to verify... despite obstacles to the investigation, notably the lack of access to documentation produced by the armed forces, officially listed as destroyed," it said.

"Under the military dictatorship, repression and the liquidation of political opponents became state policy," the commission added, insisting amnesty is incompatible with Brazilian and international law.

Brazil had already recognized some 400 deaths or disappearances under the military regime, compared with 30,000 deaths in Argentina and more than 3,200 in Chile.

Regime opponents routinely were jailed and tortured, with some summarily executed, their bodies never found.

The report quoted harrowing testimony from one, Marcia Basseto Paes, a woman arrested in 1977.

"Aside from electric shocks inside the vagina, the anus and on the breasts, they made me dance naked in front of the police," Paes recalled.

Commission coordinator Pedro de Abreu Dallari said investigators interviewed more than 1,000 witnesses over 31 months in creating the 4,400-page report.

The document, which lists 377 state officials, including now deceased former regime leaders, as being responsible for serious human rights abuses, "describes the history of each one of the 434 dead and political disappeared," Dallari told a ceremony at the presidential palace in Brasilia.

UN Secretary General Ban Ki-moon welcomed the report.

"Informing society and engaging in dialogue about fundamental freedoms, and how they have been violated, is a vital safeguard against the recurrence of abuse," Ban said in a statement.

Human Rights Watch judged the report "a major step toward addressing the atrocities committed during the country's military dictatorship" and saluted the commission for an "authoritative and long-overdue account of the horrible crimes that took place."

Amnesty International's Brazil director Atila Roque called the publication a "historic step in the country's efforts to obtain justice for crimes against humanity."

Roque added: "We must break the past cycle of impunity that fuels ongoing torture, extrajudicial executions and enforced disappearances in the present."

Rousseff, who was detained and tortured as a young political activist, created the commission in 2011 shortly after taking office.

The commission interviewed her during its research, along with former presidents Luiz Inacio Lula da Silva, her predecessor, and Fernando Henrique Cardoso.

The commission sifted through cases using evidence from judicial proceedings, public ministry documents and police investigations to produce a report which Dallari hailed as "rigorous, relevant and hard-hitting."