Mexico's top diplomat said Tuesday that President Obama has promised an investigation into spying the US reportedly did on Mexico's presidential email system.

Secretary of foreign affairs Jose Antonio Meade said Obama made the pledge during recent personal conversations by telephone and in person with Mexican president Enrique Pena Nieto.

"Mexico did not ask for an explanation. Mexico asked for an investigation," Meade said when asked whether the US had apologized or offered any explanation about the reported National Security Agency spying.

"He said and he gave his word that there was going to be an investigation around this issue," Meade said of Obama. "He said that he had not authorized any spying on Mexico."

The reports of NSA snooping have kicked up a firestorm abroad. The Brazilian president canceled a state visit to Washington, the German government canceled a Cold War-era surveillance agreement and the French government summoned the US ambassador for answers.

A report by the German news magazine Der Spiegel said documents from National Security Agency leaker Edward Snowden indicate the US gained access to former Mexican president Felipe Calderon's email system when he was in office. Earlier, a document dated June 2012 indicated the NSA had read current Mexican president Enrique Pena Nieto's emails before he was elected.

Meade called such alleged spying "an abuse of trust."

Asked whether Mexico might curtail any of its intelligence cooperation on counter-narcotics or counterterrorism because of the revelations, Meade answered: "We will be awaiting for the response before deciding whether any additional action is warranted."