The Brazilian government called in the U.S. ambassador Monday to provide explanations about new revelations that the National Security Agency's spy program directly targeted the South American giant's leader, AP reported. Ambassador Thomas Shannon arrived and left the Foreign Ministry without speaking to reporters, and there was no comment from the Brazilian side either, even as President Dilma Rousseff met separately with top ministers to discuss the case. A report by Globo TV, citing 2012 documents from NSA leaker Edward Snowden, alleges that the U.S. intercepted Rousseff's emails and telephone calls, along with those of Mexican President Enrique Pena Nieto, whose communications were being monitored even before he was elected as president in July, 2012. Sen. Ricardo Ferraco, head of the Brazilian Senate's foreign relations committee, said lawmakers already had decided to formally investigate the U.S. program's focus on Brazil because of earlier revelations that the country was a top target of the NSA spying in the region, and that the probe would likely start this week.