RIO DE JANEIRO - The Brazilian government condemned a U.S. spy program that reportedly targeted the nation's leader, labeled it an "unacceptable invasion" of sovereignty and called Monday for international regulations to protect citizens and governments alike from cyber espionage.

In a sign that fallout over the spy program is spreading, the newspaper Folha de S.Paulo reported that President Dilma Rousseff is considering canceling her October trip to the U.S., where she has been scheduled to be honored with a state dinner. Folha cited unidentified Rousseff aides. The president's office declined to comment.

The Foreign Ministry called in U.S. Ambassador Thomas Shannon and told him Brazil expects the White House to provide a prompt written explanation over the espionage allegations.

The action came after a report aired Sunday night on Globo TV citing 2012 documents from NSA leaker Edward Snowden that indicated 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.

Mexico's government said it had expressed its concerns to the U.S. ambassador and directly to the U.S. administration.

Brazilian Foreign Minister Luiz Alberto Figueiredo said, "We're going to talk with our partners, including developed and developing nations, to evaluate how they protect themselves and to see what joint measures could be taken in the face of this grave situation."

He added that "there has to be international regulations that prohibit citizens and governments alike from being exposed to interceptions, violations of privacy and cyberattacks."

Justice Minister Eduardo Cardozo said at a joint news conference with Figueiredo that "from our point of view, this represents an unacceptable violation of Brazilian sovereignty."

"This type of practice is incompatible with the confidence necessary for a strategic partnership between two nations," Cardozo said.

Earlier, 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. He said the probe would likely start this week.

"I feel a mixture of amazement and indignation. It seems like there are no limits. When the phone of the president of the republic is monitored, it's hard to imagine what else might be happening," Ferraco told reporters in Brasilia. "It's unacceptable that in a country like ours, where there is absolutely no climate of terrorism, that there is this type of spying."

During the Sunday night TV program, U.S. journalist Glenn Greenwald, who lives in Rio de Janeiro and first broke the story about the NSA program in Britain's Guardian newspaper after receiving tens of thousands of documents from Snowden, told the news program "Fantastico" that a document dated June 2012 shows that Pena Nieto's emails were being read. The document's date is the month before Pena Nieto was elected.

The document indicated who Pena Nieto would like to name to some government posts, among other information.

It's not clear if the spying continues.

As for Brazil's leader, the NSA document "doesn't include any of Dilma's specific intercepted messages, the way it does for Nieto," Greenwald told The Associated Press in an email. "But it is clear in several ways that her communications were intercepted, including the use of DNI Presenter, which is a program used by NSA to open and read emails and online chats."

The U.S. targeting mapped out the aides with whom Rousseff communicated and tracked patterns of how those aides communicated with one another and also with third parties, according to the document.

In July, Greenwald co-wrote articles in the O Globo newspaper that said documents leaked by Snowden indicate Brazil was the largest target in Latin America for the NSA program, which collected data on billions of emails and calls flowing through Brazil.

The spokesman for the U.S. Embassy in Brazil's capital, Dean Chaves, said in an emailed response that U.S. officials wouldn't comment "on every specific alleged intelligence activity." But he said, "We value our relationship with Brazil, understand that they have valid concerns about these disclosures, and we will continue to engage with the Brazilian government in an effort to address those concerns."

In Mexico City, the Mexican foreign ministry said it sent a diplomatic note to the U.S. asking for a thorough investigation of the report's claims. It said officials also summoned the U.S. ambassador to express Mexico's concerns.

"Without assuming the information that came out in the media is accurate, Mexico's government rejects and condemns any espionage activity on Mexican citizens that violate international law," the Foreign Relations Department said. "This type of practice is contrary to the Charter of the United Nations and the International Court of Justice."

The U.S. Embassy in Mexico highlighted the "close cooperation" of Mexico and the U.S. in many areas, but said it wouldn't comment on the NSA program or its alleged targeting of the Mexican leader.

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Associated Press writer Bradley Brooks reported this story in Rio de Janeiro and Marco Sibaja reported in Brasilia. Associated Press writer Michael Weissenstein in Mexico City contributed to this report.