British intelligence agency GCHQ "would not confirm of deny the existence of the Squeaky Dolphin" monitoring programme, according to NBC News.
A spokesperson for the agency said GCHQ's work was "carried out in accordance with a strict legal and policy framework”.
This "ensure[s] that our activities are authorised, necessary and proportionate, and that there is rigorous oversight, including from the Secretary of State, the Interception and Intelligence Services Commissioners and the Parliamentary Intelligence and Security Committee", the spokesperson added.
More top news
It will be a mainly dry but chilly start across the UK with a few showers across northern Scotland and northwest England.
Marks and Spencer will become the first UK retailer to add vitamin D to its entire packaged bread range.
An over-the-top 80's action movie parody featuring kung fu Hitler and a David Hasselhoff soundtrack gets almost four million views online.