The U.S. National Security Agency intercepted telephone calls and e-mails of Brazilian President Dilma Rousseff and Mexican leader Enrique Peña Nieto, Brazil's Globo television said, citing documents from whistle-blower Edward Snowden.

NSA began spying on Peña Nieto even before he won Mexico's July 2012 presidential election.

The surveillance continued during the transition, giving Washington advance knowledge of the new Mexican president's Cabinet appointments, according to a report aired Sunday on Globo's flagship news magazine, "Fantastico."

The program referred to a June 2012 "Top Secret" slide presentation touting NSA's ability to access the content of the voice and e-mail communications of both Rousseff and Peña Nieto.

The slides were among the documentation Snowden, a former U.S. intelligence contractor, provided to Brazil-based U.S. journalist Glenn Greenwald.

Rousseff, who is scheduled to visit Washington next month, discussed the revelations with her senior officials and Brazil's foreign ministry on Monday summoned U.S. Ambassador Thomas Shannon to receive a formal demand for explanations.

The Brazilian government was already uneasy about U.S. spying after O Globo reported in early July that NSA tapped into Brazil's telecommunications network via an unnamed U.S. telecom company that obtained access through one or more local partners.

O Globo, citing information from Snowden, also said the NSA and CIA maintained an intelligence listening post in Brasilia until at least 2002. EFE