REPUBLIKA.CO.ID, HONG KONG - A former National Security Agency contractor says that US hacking targets in China included the nation's mobile-phone companies and two universities hosting extensive Internet traffic hubs in the latest allegations as Washington pushes Hong Kong to extradite the ex-contractor.

The latest charges from Edward Snowden came in a series of reports published over the weekend by the South China Morning Post, Hong Kong's leading English-language daily. The newspaper, which appears to have access to Snowden, said Saturday he is still in Hong Kong and not in police custody.

On Saturday, the Obama administration warned Hong Kong against dragging out the extradition of Snowden, reflecting concerns over a possible long legal battle before he ever appears in a US courtroom to answer espionage charges for revealing two highly classified surveillance programs.

A formal extradition request would also pit Beijing against Washington at a time China is trying to deflect US accusations that it carries out extensive surveillance on American government and commercial operations.

The US has contacted authorities in Hong Kong to seek Snowden's extradition, the National Security Council said Saturday in a statement. The NSC advises the president on national security.

Snowden told the South China Morning Post that "the NSA does all kinds of things like hack Chinese cellphone companies to steal all of your SMS data." It added that Snowden said he had documents to support the hacking allegations, but the report did not identify the documents. It said he spoke to the paper in a June 12 interview.

With a population of more than 1.3 billion, China has massive cell-phone companies. China Mobile is the world's largest mobile network carrier, with 735 million subscribers, followed by China Unicom with 258 million users and China Telecom with 172 million users.

Snowden said Tsinghua University in Beijing and Chinese University in Hong Kong, home of some of the country's major Internet traffic hubs, were targets of extensive hacking by US pies this year. He said the NSA was focusing on so-called "network backbones" in China, through which enormous amounts of Internet data passes.

Snowden is believed to be hiding in an unknown location in Hong Kong, where he has been holed up since admitting to providing information to the news media about highly classified NSA surveillance programs. He has not been seen publicly since he checked out of a Hong Kong hotel on June 10.