Brazilian President Dilma Rousseff, a former Marxist guerrilla, was monitored by domestic intelligence officers after the end of the country's military dictatorship, said a media report.
The daily O Globo published files from the Strategic Affairs Secretariat of the Presidency indicating Rousseff remained under surveillance during the democratic rule of president Fernando Collor de Mello (1990-1992).
Now 64, Rousseff, Brazil's first female president, joined the battle against the military dictatorship, which ran between 1964 and 1985, at age 16 and was a member of various revolutionary groups.
In 1970, she was arrested, held for nearly three years and repeatedly tortured in the hope that she would identify her fellow guerrillas.
"Dilma's name appears in an intelligence report still linked to her activities in the opposition to the military government and with mentions of the leftist organisations she was a member of," O Globo said.
Later Rousseff worked as an official of the Rio Grande do Sul state government, where she again attracted scrutiny.
"In April 1991, Dilma's name appears in another report by infiltrated agents," this time in connection with her appointment as president of Rio Grande do Sul's Economy and Statistics Foundation, the daily noted.
O Globo said spies of the Collor de Melo government also monitored ex-president Luiz Inacio Lula da Silva, who was then head of the center-left Workers Party, now part of the ruling coalition.
The popular Lula is Rousseff's predecessor and political mentor.
Rousseff was subjected to electric shocks, and suspended from a rod by her hands and feet during the military dictatorship, according to an unedited autobiographical account published in the media.
Rousseff's torturers also often beat and threatened to disfigure her. It was revealed last month that she still has trouble chewing, after her jaw was dislocated during her jailing.
In May, Rousseff inaugurated a truth commission tasked with probing politically-motivated abductions in the Cold War era, rights abuses and murders between 1946-1988 - a time span that exceeds the dictatorship's tenure.
But the panel does not lift a 1979 amnesty law, upheld by the Brazilian Supreme Court in 2010, that paved the way for the return of political exiles while also protecting the perpetrators of dictatorship-era crimes.
According to official estimates, around 400 Brazilians were killed or disappeared during military rule, compared with 3,200 in Chile and 30,000 in Argentina.