Edward Snowden, the whistleblower who revealed secret government spying programmes, has been charged with espionage by US authorities.
A provisional arrest warrant has been issued and Hong Kong authorities have been asked to detain him.
US prosecutors have filed a criminal complaint, charging Mr Snowden with three offences including unauthorised communication of national defence information, which comes under the Espionage Act, and theft of government property.
He is also charged with willful communication of classified communications intelligence information to an unauthorised person.
All three crimes listed carry a maximum 10-year prison penalty.
The former CIA technician, who has worked for America's National Security Agency (NSA), leaked details of American telephone and internet surveillance programmes.
Court papers list three offences including theft of government property He revealed the existence of a surveillance system called Prism that was set up by the NSA to track the use of the internet directly from ISP servers.
The NSA and FBI have said that the secret programme provided "critical leads" in preventing "dozens of terrorist events" - although some terror experts dispute the claims.
President Obama has also said the programmes were carried out with "systems of checks and balances" and overseen by the courts and the US Congress.
The Prism revelations sparked outcry in the UK when The Guardian reported that the GCHQ eavesdropping agency had been accessing information about British citizens through Prism.
Mr Snowden fled to Hong Kong on May 20 after copying the last set of documents he intended to disclose at the NSA's office in Hawaii.
Protests in support of Mr Snowden have taken place in Hong Kong Sky News Asia correspondent Mark Stone said the move marks the official start of government attempts to bring him back to the US.
"We are yet to hear from the Hong Kong police and authorities on whether or not they will act on the request by the Americans to arrest Edward Snowden.
"It's my understanding that they know exactly where he is. The Americans haven't yet asked for his extradition, they have simply asked the authorities to arrest him."
There are reports a private plane is on standby to take Mr Snowden from Hong Kong to Iceland, where he hopes to get asylum.
The latest documents from Mr Snowden claim to show that British spies have secretly accessed fibre-optic cables carrying emails, Facebook messages and other communications.
The Guardian reports that GCHQ can analyse data from the network of cables that carry global phone calls and internet traffic under an operation codenamed Tempora.
It claims that communications between innocent people are being processed, as well as those from people marked out as security threats.
The NSA programme helped to prevent terror attacks, say US spy chiefs "It's not just a US problem," Mr Snowden told The Guardian.
"The UK has a huge dog in this fight. They (GCHQ) are worse than the US."
Mr Snowden worked for the NSA as an employee of various outside contractors, including Dell and Booz Allen Hamilton.
"I can't in good conscience allow the US government to destroy privacy, internet freedom and basic liberties for people around the world with this massive surveillance machine they're secretly building," Mr Snowden previously told The Guardian.
The 70mph speed limit was first introduced in the 1960s
President Jacob Zuma has said Mr Mandela's health is improving
Children have been sending "get well soon" messages to the ex-president
Current Health Secretary Jeremy Hunt (L) with Andrew Lansley
An extract from James Titcombe's letter to Andrew Lansley
Andy Burnham was Health Secretary under Labour until May 2010
Some of the extraordinary weapons being produced
This explosive device looked like a cartoon bomb
The weapons-makers are self-taught engineers
Anna Jefferson denies suggesting the CQC review should be suppressed
The Health Secretary said those behind any "cover-up" could lose pensions
Joshua Titcombe's family raised concerns after he died at Furness Hospital
Forrest is led onto a plane to be extradited from France last October
Forrest arrived back in the UK with his head covered
The family of Jeremy Forrest give their reaction to the sentencing
A jury took just two hours to find Forrest guilty of abduction
Jeremy Forrest was sentenced to five-and-a-half years in jail
Karin Williams
The overturned Audi was removed from the scene
The school is in the Vale of Glamorgan
A lollipop lady's sign could be seen lying at the side of the road
Knox was convicted in 2009
Raffaele Sollecito was Knox's boyfriend at the time of the murder
Knox was emotional in Seattle after her 2011 acquittal
Joshua Titcombe died in Furness General Hospital after staff failures
Furness General Hospital in Cumbria, which has been criticised
MP Tim Farron called for an urgent question to be tabled in the Commons
Health Secretary Jeremy Hunt is to make a statement after PMQs
Westmorland General Hospital, where Morecambe Bay NHS Trust is based
John F. Kennedy in 1963, when the Berlin Wall divided the city
Ian Brady in police custody in 1965
Myra Hindley and Ian Brady became known as the Moors murderers
Differences persist between the US and Russia over Syria 
Poles apart? David Cameron meets Russian President Vladimir Putin at the G8
Free Syrian Army fighters fire a rocket at Assad forces in Aleppo