Mexican Foreign Minister Jose Antonio Meade announced Tuesday in Geneva that he will summon the US ambassador following allegations that the United States spied on former president Felipe Calderon’s emails while he was in office.

Mexican Foreign Minister Jose Antonio Meade announced Tuesday in Geneva that he will summon the US ambassador following allegations that the United States spied on former president Felipe Calderon's emails while he was in office.

"President Enrique Pena Nieto... asked me to summon, upon my return to Mexico, the ambassador of the United States, Anthony Wayne," Meade told a press conference in Geneva where he was to participate in a UN meeting.

Nieto had on September 5 received assurances from US President Barack Obama that an investigation would be launched into allegations that his own email had been hacked into when he was running for president in 2012.

But Der Spiegel revealed on Sunday that the US National Security Agency (NSA) had snooped on Calderon's emails from May 2010, gaining access to "diplomatic, economic and leadership communications which continue to provide insight into Mexico's political system and internal stability."

The German weekly was quoting a secret document leaked by former NSA contractor Edward Snowden, who is currently living in Russia, having fled there via Hong Kong to escape US authorities pursuing him for releasing classified information.

Calderon has described the news as an "affront to the institutions of the country, given that it took place when I was president."

"Today, in the face of this new information and an unsatisfactory -- and therefore unacceptable -- response, the Mexican government wishes to stress firmly... that the probe promised by president Obama needs to be opened and broadened to include the latest elements," Meade said.

The foreign minister also said the investigation should be conducted swiftly to determine who was responsible.