Intelligence whistleblowers such as Edward Snowden will continue to leak state secrets in the public interest despite being "aggressively pursued" by the Obama administration, the president of Associated Press has said.

Gary Pruitt, the head of the global news agency, warned Washington that it cannot control the "inevitable" flow of information to the media in the wake of Snowden's disclosures about classified surveillance programs in the US and UK.

He said: "The Obama administration has made it clear that it will aggressively pursue leakers and whistleblowers. I think there will inevitably be leakers and whistleblowers, however, because there are so many people who have access to classified information."

Obama's government has "gone after leakers in a way that no other has", Pruitt said, adding that the pursuit of whistleblowers has "become a much bigger issue than I believe they thought it would be".

His comments come following the media outcry in the US over the seizure of AP phone records and the threat of criminal prosecution against a Fox News reporter. The US Department of Justice targeted the records of more than 20 phone lines of AP reporters and editors in secret in April and May in an attempt to discover the source of leaked information about a foiled bomb plot in Yemen.

Obama has ordered the Department of Justice to review its guidelines on press freedom after major news outlets warned of "government overreach". The attorney general Eric Holder is expected to report back to the president on 12 July.

But Pruitt said the incidents had threatened America's record as a "light of free press for the world". He said: "Fortunately, both the president and the attorney general have said they don't plan to prosecute journalists for doing their job. We think that should be the law, the rule, not just something they state.

"This is a free press issue. The US likes to think it has a strong free press but that was challenged in this case and we think it is important that the US not become an example where journalists are being harassed by the state."

Pruitt said there had been examples of sources being reluctant to talk to AP journalists in light of the Obama administration's high-profile pursuit of whistleblowers.

He added: "I think it goes beyond incendiary stories [such as Snowden's disclosures] to potential sources of even routine stories who may be reluctant to talk to the press because they don't want records kept on them or their phone number associated with a news gathering organisation. The government has no business owning and possessing this kind of information."

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