US should 'explain hacking activity'

Snowden leaked information to the media about PRISM, a top-secret program that collects and analyzes data from Internet users around the world. The leak has led to heated debate about privacy and civil liberty in the US.

General Keith Alexander, NSA chief and chief of US Cyber Command, told Congress on Wednesday that information collected by once-secret US surveillance programs has disrupted dozens of terrorist attacks, The Associated Press reported.

Alexander insisted that the public needs to know more about how the top-secret programs operate amid increasing unease about rampant government snooping and fears that citizens' civil liberties are being trampled.

When asked whether the US had approached China about Snowden's extradition and what Beijing's reaction would be if he applied for asylum in Hong Kong, Hua Chunying said she "has no information to offer".

Snowden said, "I have had many opportunities to flee Hong Kong, but I would rather stay and fight the United States government in the courts, because I have faith in Hong Kong's rule of law."

According to AP, US law enforcement officials are building a case against him but have yet to bring charges.

Huang Feng, an expert on international criminal law with Beijing Normal University, said the US is fully aware that it's not in an advantageous position to ask for Snowden to be sent back under its agreement with Hong Kong.

"What Snowden has done, according to US law, will fall under offences of betraying state secrets or treason. Neither of these is listed as a crime that can be used for turning over a fugitive," Huang said.

The Hong Kong government said on Thursday that it has received no report of data loss due to hacking of computer systems.