President Barack Obama has said he will not let controversial surveillance by US intelligence services undermine Washington's ties with Germany.
Speaking to Germany's ZDF TV, he indicated that US bugging of Chancellor Angela Merkel's mobile phone had been a mistake and would not happen again.
After the row broke out last year, Ms Merkel accused the US of an unacceptable breach of trust.
On Friday, Mr Obama ordered curbs on how intelligence was being collected.
Personal pledge
On Saturday, the US president told ZDF: "I don't need and don't want to harm that (US-German) relationship by a surveillance mechanism that somehow would impede the kind of communication and trust that we have."
"As long as I'm president of the United States, the chancellor of Germany will not have to worry about this."
But he added the US intelligence services, like all others, would continue to be interested in what world governments' intention were.
The interview was broadcast a day after Mr Obama ordered restrictions on the use of bulk data collected by US intelligence agencies, saying civil liberties must be respected.
Details of the times, numbers and durations of phone calls - known as metadata - are currently collected and held by the National Security Agency (NSA). But Mr Obama said he was ending that system "as it currently exists".
He asked the attorney general and the intelligence community to draw up plans for metadata to be held by a third party, with the NSA requiring legal permission to access them.
Mr Obama also stressed that such data had prevented terror attacks at home and abroad, but that in tackling threats the government risked over-reaching itself.
He also pledged that the NSA would not be spying on the leaders of close allies.
Hero or traitor?
Leaked documents last year revealed that the US had spied on friendly foreign leaders, including on the personal mobile phone of German Merkel.
A spokesman for Mrs Merkel said on Friday many Germans were "rightfully concerned" by spying reports and that the rights of foreign citizens must be respected.
He said Berlin would continue to hold confidential talks with the US on "a new clear basis for co-operation amongst intelligence agencies".
The leaked documents showed that the US had been collecting and storing almost 200 million text messages every day across the globe, according to the Guardian newspaper and Channel 4 News.
Edward Snowden, the former NSA contractor who leaked the information, is wanted in the US for espionage and is now living in exile in Russia.
Civil liberties groups see him as a hero for exposing what they see as official intrusions into private lives, but many Americans believe he has endangered American lives.