Mexican President Enrique Pena Nieto said Thursday he asked US President Barack Obama to order an investigation into allegations the National Security Agency spied on him, and punish those responsible if laws were broken. \"The Mexican government has made it clear that there must be an investigation and that there must be sanctions if there were acts that were outside international agreements and outside the law,\" Pena Nieto said from Russia in remarks aired by Mexican radio after he spoke with Obama by telephone.