Allegations that U.S. agents spied on Mexico's President Enrique Pena Nieto when he was a candidate during last year's campaign have led Mexico to summon U.S. Ambassador Anthony Wayne and demanded "a thorough investigation."
Mexico's foreign ministry says that "alleged espionage activity involving Mexican citizens" is against international law and the charter of the United Nations.
The charges that the National Security Agency spied on Nieto were broadcast over the weekend in Brazil, where reports also claim that the U.S. spied on Brazil's President Dilma Rousseff.
From Mexico City, NPR's Carrie Kahn filed this report for our Newcast unit:
"According to Brazil's Globo television, the U.S. National Security Agency spied on emails, text messages and phone calls made by Mexico's President Enrique Pena during his campaign last year. Globo cited documents obtained by Edward Snowden. The report also claimed the NSA spied on Brazil's president.
"During the TV report, an e-mail message was shown. In it, Pena Nieto writes about possible candidates for ministry posts.
"Brazil's foreign minister called the alleged spying an unacceptable breach of national sovereignty and said an upcoming visit to the White House by the Brazilian president will depend on a U.S. explanation."
The NSA has been embarrassed by several leaks this summer, after former contract worker Edward Snowden provided secret documents to journalists including The Guardian's Glenn Greenwald, who lives in Rio de Janeiro. Greenwald contributed to Sunday's report on Brazilian television.
In July, documents emerged that showed "Brazil is the top target in Latin America for the NSA's massive intelligence-gathering effort, aimed at monitoring communications around the world," the AP reported, citing the newspaper O Globo.
After the new charges of spying on top officials emerged over the weekend, Brazil summoned its U.S. ambassador, Thomas Shannon, to demand a written response to the allegations by the end of this week.