Germany said if allegations that the U.S. National Security Agency bugged European Union offices and gained access to its internal computer networks are true, then such spying on friends is "unacceptable."
A spokesman for German Chancellor Angela Merkel said Monday in Berlin mutual trust must be restored following the allegations that appeared Saturday in the German weekly Der Spiegel.
The magazine said the NSA placed listening devices in EU offices in Washington, Brussels and the United Nations in New York, and infiltrated EU computers to monitor telephone conversations, emails and other documents. It quoted secret U.S. documents leaked by former NSA contractor Edward Snowden.
U.S. Secretary of State John Kerry, who has been involved in Middle East peace negotiations, said Monday he was not aware of the reports, but that it is "not unusual" for lots of nations to engage in efforts to protect their security.
"I will say that every country in the world that is engaged in international affairs of national security undertakes lots of activities to protect its national security and all kinds of information contributes to that," Kerry said.
He discussed the issue with EU foreign policy chief Catherine Ashton on the sidelines of a regional conference in Brunei, and promised to return to those talks after learning more about the situation.
The allegations have led some in Europe to call for a suspension of talks on a trans-Atlantic trade agreement.
Snowden fled the U.S. to Hong Kong in May and then disclosed key documents about the surveillance programs being conducted by the National Security Agency to thwart terrorism.
Earlier this month, he flew to Moscow and is believed to be staying in a transit zone at the airport while seeking asylum in Ecuador.
Ecuadorian President Rafael Correa said Sunday that Snowden's fate is in the hands of Russian authorities because he cannot leave the airport without a valid U.S. passport. He said his government cannot begin considering asylum for Snowden until he reaches Ecuador or an Ecuadorian embassy.
Russia has repeatedly stated that Snowden is not on Russian territory in the airport's transit area and he is free to depart whenever he wants. Russian authorities repeated that position Sunday in response to Correa's comments.
U.S. Vice President Joe Biden asked Correa in a telephone call Friday to reject Snowden's asylum request.
According to an NSA document dated September 2010, only a few countries labeled as close friends by the U.S. are explicitly exempted from monitoring - Britain, Australia, Canada and New Zealand.