President Barack Obama sought to reassure Angela Merkel, the German chancellor, that controversial US surveillance of telephone and email records was limited and subject to strict legal controls.

“We are not rifling through the emails of German citizens or American citizens or French citizens or anyone else,” he declared in Berlin on Wednesday. “This is a circumscribed, narrow system being aimed to protect us and our people?.?.?.?The encroachment on privacy has been strictly limited.”

At a press conference in the chancellor’s office, the US president insisted that US intelligence services monitored telephone traffic simply in order to identify any telephone calls to numbers that had already been flagged as suspicious, and were only allowed to listen in to calls after submitting their request to a federal judge.