UNITED NATIONS: Brazilian President Dilma Rousseff launched a blistering attack on the United States Tuesday at the United Nations over America's widespread spying on her country.

“The argument that illegal interception of information is allegedly intended to protect nations against terrorism is untenable,” Rousseff told the opening of the UN General Assembly.

“Brazil knows how to protect itself,” she insisted, amid a damaging row over revelations of widespread spying by the US National Security Agency, including on Rousseff's email communications and on the state-run energy giant Petrobas.

Rousseff has cancelled a long planned state visit to the United States next month in anger at the revelations leaked by fugitive former CIA employee Edward Snowden,

The “recently disclosed information along the activities carried out by global network of electronic spying has brought anger and repudiation among vast sectors worldwide,” Rousseff said as she addressed the first day of the annual UN General Assembly.

“Citizens' personal data and information have been indiscriminately targeted and intercepted,” she said, speaking through a translator to the leaders of 193 nations gathered at the United Nations.

“Business information oftentimes of high economic and strategic value have been a target of spying activity,” she said.

“Meddling in such manner in the lives and affairs of other countries is in breach of international affairs and as such it is an affront to the principles.. that otherwise govern relations between countries.

“The right to security of a country's citizens can never be ensured by violating the fundamental human and civil rights of other countries.”

But US President Barack Obama who stepped up to the podium just after Rousseff insisted that while the United States was now reviewing its intelligence gathering, it had proved invaluable in the fight against terrorism.

“As a result of this work and cooperation with allies and partners, the world is more stable than it was five years ago. But even a glance at today's headlines indicates the dangers that remain,” Obama said.