President Barack Obama has said he will not let controversial surveillance by US intelligence services undermine Washington's ties with Germany, BBC reported.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.