Secretary of State John Kerry met with Poland's foreign minister Wednesday, vowing that a review into the NSA's activities will result in the "right" balance between security and privacy.
Kerry admitted Europeans and others have "legitimate" questions about the surveillance. He added that the answers will come in private diplomatic discussions.
Kerry also said outrage over alleged spying and eavesdropping should not upset key trade talks.
Meanwhile, after blasting the United States for its NSA spying allegations, Brazil is now having to defend its own surveillance practices.
On Monday, Brazil admitted to spying on diplomats from countries including the U.S., Russia, and Iran.
Folha De Sao Paulo, the newspaper that first reported the story, obtained documents from the Brazilian intelligence agency known as Abin.
According to the report, Brazil spied on property rented by the U.S. Embassy in Brasilia.
The presidential office acknowledged the spying took place, but stressed that the operations were carried out within the law.