It's claimed the US monitored the phone conversations of 35 world leaders.
The Guardian newspaper says the National Security Agency monitored the calls after getting the numbers from other government departments.
It comes as Germany and France have demanded talks with the US by the end of the year - after allegations that the German Chancellor Angela Merkel's phone was bugged.
Yesterday, the Taoiseach Enda Kenny said he always assumes his calls are being listened to - but Michael White of the Guardian says Chancellor Merkel is entitled to be angry:
