Prime Minister David Cameron on Friday (October 25) accused U.S. whistleblower Edward Snowden and unnamed newspapers of assisting Britain's enemies by helping them avoid surveillance by its intelligence services.

In his strongest remarks on the subject yet, Cameron told a news conference in Brussels that the classified information which Snowden had leaked was going to make it harder for Britain and other countries to keep its citizens safe from people who wanted to "blow up" families.

"What Snowden is doing and, to an extent, what the newspapers are doing in helping him do what he is doing, is frankly signalling to people who mean to do us harm how to evade and avoid intelligence and surveillance and other techniques," Cameron told reporters.

Cameron has criticised Britain's Guardian newspaper, which has published many of Snowden's leaks in the past, but did not mention it by name on Friday. He said people needed to adopt a "cold-hearted" view of what the intelligence services did rather than what he referred to as a "lah-di-dah airy-fairy" view.

"There are lots of people in the world who want to do us harm, who want to blow up our families, who want to maim people in our countries. That is the fact," he said.

"The first thing I'm going to do, as already explained, is to summon the U.S. ambassador in order to gather information, and thereafter we'll take the decisions we consider appropriate. We'll see once we have more information if we decide to join with what France and Germany have done. But these aren't decisions which correspond to the European Union but questions related to national security and exclusive responsibility of member states. France and Germany have decided to do one thing and the rest of us may decide to do the same, or something else. I don't have, in this very moment, the same certainty Ms. Merkel has," he said.

Presented by Adam Justice