Hong Kong is bracing itself for what could become a protracted legal battle after the NSA whistleblower Edward Snowden revealed to a local newspaper that he had no plans to leave the territory.

"I am not here to hide from justice, I am here to reveal criminality," Snowden told the South China Morning Post, adding that he had evidence of US-led cyberespionage in both Hong Kong and mainland China and that Washington had been "trying to bully" the territory into extraditing him.

Regina Ip, a member of Hong Kong's legislative council who was once the city's top security official, said: "It's not a question of bullying or not bullying. I can't speak for the Hong Kong government now, but if the US gives a request, the government will deal with it in accordance with due process."

Hong Kong, a city of seven million people, is technically a part of China but maintains an independent judiciary, media and education system. The territory has an extradition agreement with the US but can offer protection for fugitives who face political persecution or torture at home.

Chinese web portals and newspapers were awash with news of the scandal on Thursday morning, the first business day after a three-day national holiday. Snowden's revelations were "certain to stain Washington's overseas image and test developing Sino-US ties", said the China Daily newspaper in a front-page article, the first in China's state-run media to address Beijing's stance on the NSA leaks.

"For months, Washington has been accusing China of cyberespionage, but it turns out that the biggest threat to the pursuit of individual freedom and privacy in the US is the unbridled power of the government," Li Haidong, a researcher of American studies at China Foreign Affairs University, told the newspaper.

The article continued: "How the case is handled could pose a challenge to the burgeoning goodwill between Beijing and Washington given that Snowden is in Chinese territory and the Sino-US relationship is constantly soured on cybersecurity."

Beijing could intervene in Snowden's case if it decides that the outcome would affect its interests "in matters of defence or foreign affairs".

Snowden told the South China Morning Post that the NSA had hundreds of cyberespionage targets in mainland China and Hong Kong. "We hack network backbones – like huge internet routers, basically – that give us access to the communications of hundreds of thousands of computers without having to hack every single one," he said.

He named one target as the Chinese University of Hong Kong, home to a handful of advanced internet research facilities such as the Hong Kong Internet Exchange, which "essentially connects all of the city's internet access providers to a single infrastructure," the newspaper reported.

The university said in a statement that it had not detected any intrusions. "Every effort is made to protect the university's backbone network as well as the Hong Kong Internet Exchange operated by the information technology services centre of CUHK, which are closely monitored round-the-clock to ensure normal operation and defend against network threats," it said. "The university has not detected any form of hacking to the network, which has been running normally."

Local activists and civil society groups plan to express support for Snowden by marching in front of the city's government headquarters and US consulate on Saturday afternoon.

Hong Kong politicians expressed scepticism that Snowden's revelations about the NSA's cyberespionage in the territory would change the city government's attitude towards his case.

"I don't think this changes the game that much, he hasn't said a lot or given any detail," said Charles Mok, a legislative councillor and former chairman of the Hong Kong Internet Service Providers Association. "I think the Hong Kong government is still playing wait and see."

Emily Lau, chair of the city's Democratic party, said: "For those of us in the political field, we always feel as if we're under surveillance anyway, whether it's from Hong Kong authorities or mainland authorities or the US. Hong Kong for many years has been known as a spy centre – many people come here to pursue espionage activities."