The U.S. National Security Agency spied on the communications of the presidents of Brazil and Mexico, a Brazilian news program reported, a revelation that could strain U.S. relations with the two biggest countries in Latin America.

The report late Sunday by Globo’s news program “Fantastico” was based on documents that journalist Glenn Greenwald obtained from former NSA contractor Edward Snowden. Greenwald, who lives in Rio de Janeiro, was listed as a co-contributor to the report.

“Fantastico” showed what it said was an NSA document dated June 2012 displaying passages of written messages sent by Mexican President Enrique Pena Nieto, who was still a candidate at that time. In the messages, Pena Nieto discussed who he was considering naming as his ministers once elected.

A separate document displayed communication patterns between Brazilian President Dilma Rousseff and her top advisers, “Fantastico” said, although no specific written passages were included in the report.

Both documents were part of an NSA case study showing how data could be “intelligently” filtered, Fantastico said.

Justice Minister Jose Eduardo Cardozo told O Globo newspaper that the contents of the documents, if confirmed, “should be considered very serious and constitute a clear violation of Brazilian sovereignty.”

via U.S. spied on presidents of Brazil, Mexico: report | Reuters.