Washington: Even as the White House was grappling with allegations that America had tapped the mobile phone of the German Chancellor Angela Merkel new claims have emerged that the US was spying on 35 world leaders.

The phones were monitored after the National Security Agency was given the personal phone numbers of the leaders by another US official, according to a 2006 memo leaked to the Guardian newspaper by former NSA staffer Edward Snowden.

Phone tapping fears: German Chancellor Angela Merkel. Credit:AP

Senior official of key US agencies and departments such as the White House, State Department and Pentagon were encouraged to hand over the contact lists to the intelligence agency in order to facilitate the phone tapping, the Guardian reports.

"We are not going to comment publicly on every specific alleged intelligence activity, and as a matter of policy we have made clear that the United States gathers foreign intelligence of the type gathered by all nations," a White House spokeswoman said, in response.