Two US sources, speaking on condition of anonymity, said the United States was preparing to seek Snowden’s extradition from Hong Kong, which is part of China but has wide-ranging autonomy, including an independent judiciary.

Documents leaked by Snowden and revealed by him in Hong Kong showed that the NSA had access to vast amounts of internet data such as emails, chat rooms and video from large companies such as Facebook and Google, under a government program known as Prism.

The Washington Post said the United States had asked Hong Kong to detain Snowden on a provisional arrest warrant.

Hong Kong Police Commissioner Andy Tsang declined to give details but said Hong Kong would deal with the case in accordance with the law.

“The laws that are enforced in Hong Kong are Hong Kong laws, not foreign laws,” he told reporters.

The Apple Daily newspaper said police had provided Snowden with a safe house and protection. Police had checked his documents to make sure he hadn’t overstayed but didn’t talk to him on other matters or take any statement, the paper said, citing police sources.

The US Consulate referred inquiries to the US Department of Justice in Washington.

Hong Kong legislators said that the Chinese government should make the final decision on whether former National Security Agency contractor Edward Snowden should be extradited to the United States now that the Justice Department has charged him with espionage and theft of government property.

Outspoken legislator Leung Kwok-hung said Beijing should instruct Hong Kong to protect Snowden from extradition before his case gets dragged through the court system. Leung also urged the people of Hong Kong to “take to the streets to protect Snowden.”

Another legislator, Cyd Ho, vice-chairwoman of the pro-democracy Labour Party, said China “should now make its stance clear to the Hong Kong SAR (Special Administrative Region) government” before the case goes before a court.

It is not known if the US government has made a formal extradition request to Hong Kong.

When China regained control of Hong Kong in 1997, the former British colony was granted a high degree of autonomy and granted rights and freedoms not seen on mainland china. However, under the city’s mini constitution Beijing is allowed to intervene in matters involving defence and diplomatic affairs.

The United States and Hong Kong signed an extradition treaty which came into effect in 1998.

China has urged Washington to provide explanations following the disclosures of National Security Agency programs which collect millions of telephone records and track foreign internet activity on US networks, but it has not commented on Snowden’s status in Hong Kong.

He said in an interview with the South China Morning Post that he hoped to stay in the autonomous region of China because he has faith in “the courts and people of Hong Kong to decide my fate.”

He and his supporters have also spoken of his seeking asylum from Iceland.

A prominent former politician in Hong Kong, Martin Lee, the founding chairman of the Democratic Party, said he doubted whether Beijing would intervene at this stage.

“Beijing would only intervene according to my understanding at the last stage. If the magistrate said there is enough to extradite, then Mr. Snowden can then appeal,” he said.

Lee said Beijing could then decide at the end of the appeal process if it wanted Snowden extradited or not.

While espionage and theft of state secrets are not cited specifically, equivalent charges could be pressed against Snowden under Hong Kong’s Official Secrets Ordinance, legal experts say.

Snowden, however, could claim political asylum. Under article six of the treaty, extradition should be refused for “an offence of a political character”.

Legal sources in Hong Kong say Snowden has already approached prominent human rights lawyers in preparation for a protracted extradition battle.

If Hong Kong authorities don’t charge him with an equivalent criminal act, authorities cannot arrest or take legal action. He was also theoretically free to leave the city, one legal expert said.

Simon Young, a law professor at the University of Hong Kong, said a formal extradition request would likely be made through diplomatic channels to Hong Kong’s chief executive, who must decide whether or not to issue an “authority to proceed”.

A magistrate would then issue a warrant for the arrest and then decide whether there was sufficient evidence to commit Snowden to trial.

While China has veto power over extradition proceedings if its “defence or foreign affairs would be significantly affected”, this power has rarely been invoked by Beijing for previous cases involving non-Chinese nationals.

“If he requested asylum, then from a humanitarian standpoint, we should protect him,” said 60-year-old resident Elli Fan near a street-side banner saying “Protect Snowden. Protect Freedom.”

An Icelandic businessman linked to the anti-secrecy group WikiLeaks said on Thursday he had readied a private plane in China to fly Snowden to Iceland if Iceland’s government would grant asylum.

A one-page criminal complaint unsealed Friday in federal court in Alexandria, Virginia, said Snowden engaged in unauthorised communication of national defence information and wilful communication of classified communications intelligence information. Both are charges under the Espionage Act. Snowden also is charged with theft of government property. All three crimes carry a maximum 10-year prison penalty.

The complaint will be an integral part of the US government’s effort to have Snowden extradited from Hong Kong, a process that could become a prolonged legal battle. Snowden could contest extradition on grounds of political persecution.

Hong Kong lawyer Mark Sutherland said that the filing of a refugee, torture or inhuman punishment claim acts as an automatic bar on any extradition proceedings until those claims can be assessed.

“Some asylum seekers came to Hong Kong 10 years ago and still haven’t had their protection claims assessed,” Sutherland said.

Organisers of a public protest in support of Snowden last week said on Saturday there were no plans for similar demonstrations this weekend.

Reuters and Associated Press