US federal prosecutors have filed a sealed criminal complaint against Edward Snowden and charged him with espionage, The Washington Post reported on Friday on its website.

Snowden, a former defense contractor and leaker of classified surveillance programs of the National Security Agency (NSA), was charged with espionage, theft and conversion of government property, the newspaper quoted US officials as saying.

US prosecutors have asked China's Hong Kong Special Administrative Region, where the 29-year-old is believed to have fled, to detain him on a provisional arrest warrant, US officials told the newspaper.

The complaint was filed in the Eastern District of Virginia, a jurisdiction where Snowden's former employer, Booz Allen Hamilton, is headquartered and a district with a long track record of prosecuting cases with national security implications.

Two classified NSA surveillance programs, one collecting US phone records and the other monitoring internet data, were revealed earlier this month after leaks from Snowden.

According to media reports, under the internet surveillance program dubbed PRISM, the NSA and the FBI had been secretly tapping directly into the central servers of nine US internet companies, extracting audio, video, photographs, emails, documents and connection logs that enable analysts to track a person's movements and contacts over time.

Snowden admitted to leaking details of two top-secret NSA surveillance programs on June 9. The US Justice Department has since confirmed that a criminal investigation had been launched into the disclosures.

President Barack Obama and officials of the US intelligence community have stressed that the internet surveillance program targeted foreigners and helped thwart terror plots.

Speaking at a hearing last week, FBI Director Robert Mueller vowed to take "all necessary steps to hold the person responsible for these disclosures," but declined to comment publicly on the details of the ongoing investigation.