EU regulator warns Yahoo after email scanning

Yahoo's scanning of its customers' emails at the behest of US intelligence authorities has provoked a reaction from the European Union, and instigated doubt about the new trans-Atlantic data sharing deal.

On Wednesday, it was reported that Yahoo complied with a directive from US security agencies to scan emails, searching for specific information.

Now the lead European regulator on data issues has stepped in to say he will be looking into the matter.

"Any form of mass surveillance infringing on the fundamental privacy rights of EU citizens would be viewed as a matter of considerable concern," Ireland's Data Protection Commissioner said in a statement.

Yahoo has not yet said whether European accounts were accessed as a result of the search.

The email incident could have consequences for European businesses, such as British-listed Sky and BT, which use Yahoo email servers.

A new data-sharing deal was announced in February between the USA and Europe, known as the "Privacy Shield", and some European politicians have said that Yahoo's actions would not be consistent with the deal.

A spokesperson for the European Commission, the EU's executive branch, said that the US will be held responsible if there is any breach of the deal.

"The U.S. will be held accountable to these commitments both through review mechanisms and through redress possibilities," the spokesman said.