Washington - Allegations of US spying on Brazil's president and on its state oil company raise "legitimate questions", a US official said on Wednesday during talks with Brazil's foreign minister.
Luiz Alberto Figueiredo met US National Security Adviser Susan Rice to discuss reports of the reported surveillance by the National Security Agency.
Rice told Figueiredo "the United States understands that recent disclosures in the press - some of which have distorted our activities and some of which raise legitimate questions for our friends and allies about how these capabilities are employed - have created tensions...," spokesperson Caitlin Hayden said after the talks.
"The United States is committed to working with Brazil to address these concerns...," she added.
Brazilian broadcaster TV Globo has reported that the NSA eavesdropped on Brazilian President Dilma Rousseff, some of her aides and the state oil giant Petrobras.
They based their reports on information from Glenn Greenwald, a blogger and columnist for the Guardian newspaper, who got secret files from former US intelligence contractor Edward Snowden.
When the first allegations emerged at the beginning of the month, Brazil's government summoned the US ambassador over the affair.
Rousseff has also halted preparations for a visit to the United States, scheduled for 23 October, pending an explanation from Washington over the allegations.
The alleged US espionage targeting Petrobras however will not delay an oil field auction scheduled for next month, a Brazilian government official was quoted as saying this week.
The discovery of the enormous so-called Libra field marked the largest oil discovery in Brazilian history.
It is believed to hold between eight and 12 billion barrels of recoverable oil, and covers an area of 1 500km2 in ultra deep oil fields detected in 2007.
Figueiredo did not speak with reporters after the discussions, but a diplomatic source told AFP he would remain in Washington overnight Wednesday, and that the talks would continue.