Snowden

Edward Snowden during an interview in Hong Kong with reporters for the Guardian newspaper. (Guardian / June 10, 2013)

MEXICO CITY — The U.S. habit of spying on Mexico extended to former President Felipe Calderon despite the close bonds he forged with his powerful northern neighbor, the German magazine Der Spiegel alleged Sunday.

Der Spiegel said its report was based on top-secret National Security Agency documents leaked by former U.S. intelligence contractor Edward Snowden. The documents purportedly show that the NSA gained access to an email server used by Calderon and his Cabinet.

As a result, the magazine said, quoting NSA documents, the U.S. monitored a wealth of "diplomatic, economic and leadership communications" that enabled it to gauge the "internal stability" of Mexico.

Allegations of U.S. spying on Mexico have sparked intense debate here after reports in July and September, which also were based on Snowden leaks. The September report alleged that the U.S. had spied on the current president, Enrique Peña Nieto, while he was campaigning.

Some Mexicans will consider it particularly galling that the U.S. targeted Calderon. The conservative president, who served from 2006 to 2012, allowed U.S. security agencies an unprecedented amount of access to Mexico in an effort to fight off the powerful drug cartels. Some here viewed the increased U.S. presence as a breach of Mexican sovereignty.

Snowden's leaks also have revealed U.S. spying on other allied countries in Latin America. Brazil reacted with particular pique; President Dilma Rousseff last month canceled her planned state visit to the U.S. and, during a fiery speech to the United Nations, denounced U.S. meddling.

Mexico's reaction has been less forceful, but it has won assurances from the Obama administration to investigate. On Sunday, the Mexican Foreign Ministry demanded that the investigation be "concluded shortly," and it reiterated that U.S. spying on Mexico was "unacceptable, unlawful and contrary to Mexican law and international law."

A spokesman for the American Embassy in Mexico said the U.S. would not comment on the specific allegations. "As a matter of policy, we have made clear that the United States gathers foreign intelligence of the type gathered by all nations," the embassy said in a statement.

The U.S. and Mexico "are strategic partners and enjoy close cooperation on many fronts," the statement said, adding that Presidents Obama and Peña Nieto "share a desire to work more closely to bring prosperity and security to our citizens."

richard.fausset@latimes.com