Sao Paulo , Brazil ( CNN ) -- Brazil and Mexico summoned U.S. ambassadors Monday after media reports that the United States had spied on their countries ' presidents . `` Without prejudging the veracity of the information presented in the media , the Mexican government rejects and categorically condemns any espionage work against Mexican citizens in violation of international law , '' Mexico 's foreign ministry said in a statement . In Brazil , Foreign Minister Luiz Alberto Figueiredo called the situation `` an inadmissible and unacceptable violation of Brazilian sovereignty . '' The statements were the latest sign of international fallout over documents leaked by former National Security Agency contractor Edward Snowden . A Brazilian news report Sunday described the alleged espionage , citing Glenn Greenwald , a Brazil-based journalist who obtained documents from Snowden . CNN has not independently confirmed the report , and there was no immediate reaction from the White House . Source : U.S. seeks compromise on companies ' NSA data requests . The report first appeared in Globo TV 's Sunday night program `` Fantastico '' and is likely to heighten tensions between the United States and Latin America 's two biggest economies . One of the alleged NSA documents leaked to Greenwald dates from June 2012 , a month before Mexican President Enrique Pena Nieto was elected . In it , the candidate talks about whom he would select for his Cabinet if elected . The documents did not reference any specific communications with Brazilian President Dilma Rousseff but show the methods the NSA allegedly used to track e-mails and mobile phone communications with close advisers . `` It was very clear in the documents that they had already carried out the spying , '' Greenwald told `` Fantastico , '' speaking in Portuguese . `` They are n't talking about something they are planning , they are celebrating their spying successes . '' Brazilian Justice Minister Eduardo Cardozo told CBN radio : `` If it 's confirmed , it is very serious because a country can not passively accept the violation of its sovereignty . '' `` Any country that has its sovereignty violated has to react , take a position and use international law to put things in their place , '' he added . `` And that 's what Brazil will do . '' A spokesman for Mexican President Enrique PeÃ±a Nieto declined to comment Monday morning . Data seized from Greenwald 's partner Miranda risks security , UK says . Mexican lawmakers stressed that the Brazilian news report had not been confirmed but demanded further explanation from the U.S. government . `` This new revelation is extremely delicate because any kind of espionage is an irregular situation that is against the law . However , we have to be clear that this is speculation . This is a leak , and it must be treated like one , '' said Sen. Marcela Guerra . Guerra , a member of the ruling Institutional Revolutionary Party and president of the Senate 's North American foreign relations committee , said Mexico 's foreign minister should meet with the U.S. ambassador to Mexico over the matter . `` There is a feeling of deep indignation , '' even though the report has n't been proven , said Rep. Fernando Zarate , secretary of the Mexican house of representatives ' foreign relations committee . `` If true , it seriously violates national sovereignty , '' said Zarate , of the Democratic Revolution Party . `` How is it possible that the telephone of a president is being monitored ? What could an ordinary citizen in our country expect ? '' In Brazil , bilateral relations were already strained by reports that the South American nation was one of the countries that had been most-targeted by the NSA spying program . Rousseff is scheduled to visit U.S. President Barrack Obama in Washington in October . Obama visited Mexico in May , stressing the importance of strengthening educational and economic ties between the two nations . NSA misrepresented scope of data collection to secret court . CNN 's Shasta Darlington reported from Sao Paulo . CNN 's Catherine E. Shoichet reported from Atlanta . Journalist Nick Parker and CNNMexico.com 's Mauricio Torres and CNN 's Ariel Crespo contributed to this report from Mexico City .
NEW : Brazil 's foreign minister decries an `` unacceptable violation '' of the country 's sovereignty . Mexico summons the U.S. ambassador to demand an investigation . Journalist Glenn Greenwald tells Brazil 's Globo TV about NSA documents . He says one document is on Mexico 's soon-to-be president discussing his Cabinet picks .