China has warned that revelations of electronic surveillance on a huge scale by American intelligence agencies will "test developing Sino-US ties" and exacerbate their "soured relationship" on cybersecurity.

The assessment in an article and editorial carried by the state-run China Daily represents the first official comment in state media as China grapples with the presence in Hong Kong of Edward Snowden, the US analyst who revealed himself as the source of the Guardian exposé.

Quoting analysts, the China Daily article said the "massive US global surveillance programme … is certain to stain Washington's overseas image" and pointedly referred to Washington recently levelling claims of hacking at other governments, including China's.

"Observers said 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," the paper said.

On Wednesday, Snowden commented for this first time since disclosing his identity as the source of a series of leaks from the US National Security Agency (NSA). In an interview with the South China Morning Post, he vowed not to "hide from justice" and would put his trust in the Hong Kong legal system.

Snowden also claimed that the US had been hacking Hong Kong and China since 2009. He that the US had hacked hundreds of targets in Hong Kong – including public officials, a university, businesses and students in the city – and on the mainland.

In his interview, Snowden said he was releasing the information to demonstrate "the hypocrisy of the US government when it claims that it does not target civilian infrastructure, unlike its adversaries".

Jen Psaki, a spokeswoman for the State Department in Washington, said it was not aware of the hacking claims and could not comment directly, but she rejected the idea that such an incident would represent double standards given recent US criticism of Chinese cyber attacks.

"There is a difference between going after economic data and the issues of surveillance that the president has addressed which are about trying to stop people doing us harm," she said.

The China Daily article addressed the issue directly. It quoted Li Haidon, a researcher of American studies at the China Foreign Affairs University, as saying: "For months Washington has been accusing China of cyber-espionage 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."

The report gave no indication of what tack Beijing might take on Snowden's stated intention of fighting extradition from Hong Kong, which is Chinese territory but has a separate legal system. It is unclear whether or not authorities on the mainland would intervene over any US attempt to extradite Snowden. The paper referred only to Russia's offer to consider an asylum request. It added that Hong Kong supporters of Snowden would stage a protest march to the US consulate on Saturday afternoon.

Zhang Tuosheng, a researcher at the China Foundation for International and Strategic Studies, was quoted as saying that if the US and China were able to successfully handle the case it would form "an influential precedent between the two countries, since there has been a lack of international regulations in the area of global internet security".

In a separate editorial under the headline "Unjustified US intelligence", the China Daily said controversy over US drone strikes had already forced [Barack] Obama to "readjust this widely maligned policy" and suggested the NSA revelations demanded a similar response of the US president.

"This is not the first time that US government agencies' wrongdoings have aroused widespread public concern since the US launched a series of counterterrorism policies to enhance national security after the terrorist attacks on Sept 11 2001," the paper said.

"The Obama administration needs to convince the American people as well as global internet users that the spying is a must and helps in a direct way to safeguard public safety from clear and present dangers.

"But it will have difficulty in doing so, as the bombing of the Boston marathon provides ready proof of the fact that extremists and terrorists, even when working alone, can inflict a heavy blow despite all the efforts that have been made globally to rein in terrorism.

"The Obama administration may want to adjust the boundaries of its counterterrorism policies so that infringements on individual rights are not as expansive."

The Hong Kong government has not taken a public position on the case. The chief executive of the Hong Kong government, Leung Chun-ying, on a visit to New York, repeatedly refused to comment in a Bloomberg Television interview.

Snowden, 29, was a computer technical assistant working for Booz Allen Hamilton, on contract to the NSA. He left his job and home in Hawaii in May, set up camp in Hong Kong and provided the Guardian with top-secret documents that led to a series of revelations about the extent of US surveillance last week. For three weeks he stayed in a hotel in the Kowloon district. But after identifying himself as the whistleblower in a video posted by the Guardian on Sunday he felt he needed to move to a more secure location and checked out on Monday.

Hong Kong appeared a strange choice for Snowden, as it has a surrender treaty with the US and leans towards co-operating with Washington's requests. But in his South China Morning Post interview Snowden said: "People who think I made a mistake in picking Hong Kong as a location misunderstand my intentions. I am not here to hide from justice. I am here to reveal criminality."

As a debate raged in the US over whether Snowden should be praised or prosecuted for his actions, he said: "I'm neither traitor nor hero. I'm an American."

In Washington an outspoken Republican congressman, Peter King, called for the arrest of the Guardian columnist who led the reporting on the NSA leaks, Glenn Greenwald. King told Fox News that Greenwald's stories were "putting American lives at risk and clearly done to hurt Americans". In a statement, the Guardian said it was "surprised and disappointed" by the comments.

In another development, the British foreign secretary, William Hague, rejected suggestions that US surveillance programs were being used by UK authorities to avoid local privacy laws and spy on British citizens. On a visit to Washington where he met the US secretary of state, John Kerry, Hague said: "No two countries in the world work more closely to protect the privacy of their citizens than the United Kingdom and the United States."

Kerry said they both understood the "very delicate but vital balance between privacy and the protection of people in our country".