The United States maintained a satellite spy base in Brazil, the only one in Latin America, until at least 2002, the daily O Globo reported Monday, citing documents leaked by Edward Snowden.
The satellite intelligence collection base in Brasilia was jointly operated "at least until 2002 by the NSA (National Security Agency) and the Central Intelligence Agency," the report said.
O Globo on Sunday reported that the NSA spied on Brazilian residents and companies as well as people traveling in Brazil, again citing documents obtained from Snowden.
The Brazilian government described the allegations as "extremely serious" and said it would seek explanations from Washington.
Meanwhile the daily Folha de Sao Paulo said President Dilma Rousseff discussed the affair with Justice Minister Jose Cardozo and Communications Minister Paulo Bernardo Sunday.
"The president was very concerned. I would even say outraged," the paper quoted Bernardo as saying.
The minister said federal police and the national telecom agency ANATEL would launch an investigation, according to Folha de Sao Paulo. But there was no official confirmation.
O Globo said the US facility in Brasilia was part of a network of 16 "Primary Fornsat Collection Operations" maintained by the NSA around the world to intercept transmissions from foreign satellites.
Brazil leases eight satellites.
The daily said it did not have enough evidence to say whether the US operation continued after 2002.
The daily also published an NSA document dated September 2010 which seemed to indicate that the Brazilian embassy in Washington and the Brazilian mission to the UN in New York were targeted by the agency.
The new reports came as Snowden faced the logistical nightmare of escaping Russia for a safe haven in Latin America after the leftist leaders of Bolivia, Venezuela and Nicaragua all offered him asylum.
All three have strained ties with Washington and represent Snowden's best options after his rejection by many of the 27 nations to which he had applied for protection.
Washington has urged Russia to hand over Snowden as a gesture of good will because the two sides have no extradition agreement.