Mexico scolded the United States on Sunday over new allegations of spying after a German magazine reported that the U.S. National Security Agency (NSA) had hacked Felipe Calderon's public email account while he was president.
Weekly Der Spiegel said in May 2010, an NSA division known as "Tailored Access Operations" reported it had gained access to then-president Calderon's email account, and turned his office into a "lucrative" source of information.
It said details of the alleged NSA hacking of Calderon's account were contained in a document leaked by former NSA contractor Edward Snowden. Snowden's leaked information has prompted angry recriminations against Washington in Latin America, particularly Brazil.
According to Der Spiegel, the NSA succeeded in hacking a central server in the network of the Mexican presidency that was also used by other members of Calderon's cabinet, yielding a trove of information on diplomatic and economic matters.
Without citing by name the German report, which was picked up by a number of Mexican media, the Mexican foreign ministry condemned the latest allegations about "suspected acts of spying carried out by the National Security Agency."
"This practice is unacceptable, illegal and against Mexican and international law," the ministry said in a statement.
Mexico is one of the United States' biggest trading partners and the report could damage ties as the two sides seek to improve cooperation on issues like cross-border security, migration and fighting organized crime.
The ministry said President Barack Obama had pledged to carry out an "exhaustive investigation" into who was responsible for the suspected espionage in his latest meeting with President Enrique Pena Nieto, who succeeded Calderon in December.
"In a relationship between neighbors and partners there is no place for the actions that allegedly took place," it added.
Pena Nieto, who according to separate reports was also a victim of NSA spying before he took office, had already called the alleged U.S. espionage "unacceptable" in July.
Still, Mexico, which sends nearly 80 percent of its exported goods to the United States, has so far offered a more restrained response to the spying allegations than Brazil.
Last month, Brazilian President Dilma Rousseff suspended plans for a state visit to Washington due to revelations the NSA had snooped on her communications, and she later blasted the United States over spying at the U.N. General Assembly.