A 29-year-old government contractor has revealed himself as the source of disclosures about the US government's secret surveillance programmes.

Edward Snowden, a former CIA technician who has contracted for the National Security Agency (NSA), admitted his role in leaks to The Guardian and The Washington Post newspapers, saying the public needs to decide whether the programmes are right or wrong.

He told The Guardian he has nothing to hide.

The recent stories in The Guardian and The Washington Post have revealed the existence of the PRISM system, a surveillance program set up by the NSA that tracks the use of the internet directly from ISP servers.

Mr Snowden, currently holed up in a Hong Kong hotel, risks prosecution.

The leaks have led the NSA to ask the Justice Department to conduct a criminal investigation. The Justice Department said it was in the initial stages of an investigation.

Mr. Snowden worked for the NSA as an employee of various outside contractors, including Dell and Booz Allen Hamilton, his current employer.

He flew to Hong Kong on May 20th after copying the last set of documents he intended to disclose at the NSA's office in Hawaii, the reports said.

The Guardian and The Washington Post said they were revealing Mr. Snowden's identity at his own request.

"I'm not going to hide," Snowden told The Post. "Allowing the US government to intimidate its people with threats of retaliation for revealing wrongdoing is contrary to the public interest."

He acknowledged fears of being "rendered" - summarily detained without due process and taken into secret detention by the CIA or its partners - or taken in for questioning by Chinese authorities.

"And that is a concern I will live with for the rest of my life, however long that happens to be," he said.

Mr Snowden said he is seeking "asylum from any countries that believe in free speech and oppose the victimisation of global privacy".

"The nation that most encompasses this is Iceland. They stood up for people over internet freedom."

Iceland's International Modern Media Institute, a free press group, said it had yet to hear from Mr. Snowden directly. But in a statement the institute said it would do what it could to help him find asylum and was working to set up a meeting with Iceland's interior minister.

However, the law appears to allow for Mr. Snowden extradition from Hong Kong, a semiautonomous territory of China, to the United States.

The revelations spurred an outcry, which expanded when The Guardian said the UK's Government Communications Headquarters (GCHQ) monitoring centre has been accessing information about British citizens through Prism.

GCHQ is due to give a report to the Intelligence and Security Committee of the British parliament over its links with the programme.

UK Foreign Secretary William Hague defended the integrity of GCHQ, dismissing as "fanciful" claims that the eavesdropping centre has stepped outside the law.

A separate programme, also disclosed by The Guardian, has been used to scoop up the telephone records of millions of Americans.

US President Barack Obama described the secret programmes as vital to keeping Americans safe, saying the US is "going to have to make some choices between balancing privacy and security to protect against terror".

Mr. Snowden said he has no regrets, even as he predicts that he might not see his home again.

A native of North Carolina, Mr. Snowden said he lacked a high school diploma and enlisted in the US Army in 2003 because he wanted to fight in Iraq.

He was discharged after breaking his legs in training and took a job as a security guard at an NSA facility in Maryland.

He later joined the CIA where he worked on IT security. He said he started becoming disillusioned during a stint in Geneva where he had access to classified documents.

"I realised that I was part of something that was doing far more harm than good," he was quoted as saying.

He left the CIA in 2009 and joined a private contractor that assigned him at an NSA facility in Japan, where, he said, he "watched as Obama advanced the very policies that I thought would be reined in".

His current employer, Booz Allen, said Mr. Snowden had worked there "for less than 3 months". The firm promised to work with the authorities on the investigation.

The director of national intelligence, James Clapper, said two plots had been foiled through information obtained through Prism and phone snooping programmes.

Both were in 2009, he said - one was a bomb attack on the New York subway, and the other was linked to David Headley, a conspirator in the 2008 Mumbai attacks.

Under PRISM, which has been running for 6 years, the NSA has been able to issue directives to internet firms demanding access to e-mails, online chats, pictures, files, videos and more uploaded by foreign users.

Internet service providers, like Google and Facebook, have denied giving the government unfettered access to customer data, insisting have only done so only when compelled by law.

It is understood US authorities have initiated criminal proceedings against Snowden.