The revelation that Britain and America had a list of surveillance targets which included the Israeli Prime Minister, a European Union commissioner and various charities, has prompted an angry response.
The European Commission issued a statement saying the claims "deserve our strongest condemnation" if proved true.
"This is not the type of behaviour that we expect from strategic partners, let alone from our own member states," it said.
Unicef and Medecins du Monde were among the organisations listed in the latest batch of secret documents leaked by fugitive Edward Snowden to be published by the Guardian.
Leigh Daynes, an executive director of Medecins du Monde in the UK, told the Guardian he was "shocked and surprised by these appalling allegations of secret surveillance on our humanitarian operations".
More top news
A British journalist based in Egypt has been expelled from the country as authorities tighten control over the media ahead.
Airline fees for services such as name changes and airport check-in could be targeted under a new Government clampdown.
Poisoned double agent Sergei Skripal asked Vladimir Putin to be pardoned and requested he be allowed to visit Russia, according to a friend.