BRASILIA: President Dilma Rousseff said the Obama administration was not directly responsible for US spying on Brazil and has taken steps toward smoothing over the diplomatic tensions set off by espionage disclosures last year.

In an interview with CNN's Christiane Amanpour broadcast on Thursday, Rousseff said she understood that the Obama administration needed time resolve what was happening and could not immediately provide explanations demanded by Brazil.

Documents leaked by former National Security Agency analyst Edward Snowden revealed that Rousseff's personal phone calls and e-mails, and those of other Brazilians, had been spied on by secret US eavesdropping programs used to monitor the Internet.

The revelations froze relations between Brazil and the United States. Outraged, Rousseff cancelled a rare state visit to Washington and demanded an apology from President Barack Obama. The United States has publicly regretted the incident but has so far stopped short of issuing a formal apology.

"I do not believe the responsibility for the spying habits lay with the Obama administration. I think this was a process that began after Sept 11," Rousseff said on CNN, in reference to the 2001 attacks on New York and Washington that led the United States to tighten security measures and step up surveillance of the Internet to identify terrorist threats.

Rousseff said the US spying on Brazilian citizens and companies was an unacceptable violation of the right to privacy and freedom of expression. Brazil sought guarantees that the spying had stopped but they were not forthcoming, she said.

"At the time, the Obama administration was busy trying to resolve that problem of international espionage and was unable to gives us a reply," Rousseff said.

"Today, I think they have taken several steps," she added, without giving details of what Washington has done on the issue.

In an attempt to put relations with Latin America's largest nation back on track, vice-president Joe Biden visited Rousseff last month and had a "candid" talk about Internet surveillance with the leftist Brazilian leader.

Days earlier, Rousseff told foreign reporters that she was eager to rebuild relations with the United States and said in an interview with the New York Times that she was ready to reschedule her visit to Washington. — Reuters