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
Nick Clegg has sent a campaign leaflet to his constituents with no Liberal Democrat logo and minimal mention of the party.
Rain continues to move eastwards in the south tonight, the north, frosty with the clear skies.
Daily Dose, a short summary of the day's election campaign stories.