Brazil's government says it will investigate reports that the United States monitored the telephone and email activities of Brazilians.
The announcement comes after the O Globo newspaper reported Sunday that the U.S. National Security Agency collected data on billions of telephone and email conversations in Brazil. The paper cited documents leaked by former NSA contractor Edward Snowden.
O Globo also reported that some of the access to the communications was obtained from American companies that are partners with Brazilian companies.
Brazil's government said Monday it will also investigate whether telecommunications firms operating in Brazil cooperated with the United States in its alleged spying activities.
The O Globo article was co-authored by Glenn Greenwald, the journalist who first revealed classified documents leaked by Snowden.
In another development, Cuban President Raul Castro voiced his support for three Latin American nations offering asylum to Snowden.
Mr. Castro said he supports the right of all countries in the region to grant asylum to those "persecuted for their ideals."
The leaders of Venezuela, Nicaragua and Bolivia have said they would take in the 30-year-old Snowden.
It is not clear how Snowden will get to any of the Latin American nations. The Cuban government has not said whether it would allow him to pass through.
Snowden is believed to be in the transit area of Moscow Airport since arriving on a flight from Hong Kong two weeks ago, unable to travel farther because the United States annulled his passport.
Snowden has sought asylum in more than 20 countries. But most of them have either turned him down or said he must be in their countries or one of their embassies before they will consider his asylum bid.
American authorities want him extradited to the U.S. to stand trial on espionage charges, but Russian President Vladimir Putin has refused, even as he says he wants Snowden to leave for another country.
The NSA says the information it has collected helped foil terrorist attacks. Snowden has said Americans should know their government has them under surveillance.