State-run media in Beijing hit out on Friday at suggestions that China was behind a massive cyber-spying initiative uncovered this week by a top security firm.
A commentary in the People's Daily newspaper, the public voice of the ruling Communist Party, said the claims were "irresponsible."
"It is irresponsible to link China to Internet hackers," the paper said.
Security giant McAfee said Wednesday that hackers compromised computer security at more than 70 global organizations, including the U.N. and U.S. government bodies.
In a report titled "Operation Shady RAT," McAfee said it had managed to gain access to the logs of a single server that had penetrated cyber security at so many organizations that the problem of cyber-spying was probably even more widespread than its evidence suggested.
"This is a problem of massive scale that affects nearly every industry and sector of the economies of numerous countries, and the only organizations that are exempt from this threat are those that don’t have anything valuable or interesting worth stealing," McAfee vice president of threat research Dmitri Alperovitch wrote in the report.
McAfee did not identify any country behind the hacking campaign, which it traced back to as far as five years ago, but James Lewis, a cyber-security expert at the Center for Strategic and International Studies, said that suspicion pointed towards China.
"You can think of at least three other large programs attributed to China that look very similar," Lewis told Agence France-Presse. "It's a pattern of activity that we've seen before. It's in line with other activities."
But China's official Xinhua news agency quoted Alperovitch on Friday as saying that there wasn't enough evidence to point the finger at any one country.
Alperovitch told the agency that McAfee lacked "direct evidence that conclusively points to a particular nation state" behind the scheme.
Speculations that China was behind the massive cyber-espionage activity stemmed from the possible link to the Olympics, the targeting of a Hong Kong-based reporting bureau, and previous accusations by Google, which said its systems were hacked and targeted by various attacks originating in China.
Alperovitch said that the logs accessed by McAfee had shown a huge spike in the pace of spying activity in 2007, when it "jumped by a whopping 260 percent to a total of 29 victim organizations."
Two Asian Olympic Committees and one Western Olympic Committee were compromised during that year, rising to 36 victims in 2008, the year that Beijing hosted the Olympic Games.
"Even news media [were] not immune to the targeting, with one major U.S. news organization compromised at its New York Headquarters and Hong Kong Bureau for more than 21 months," the McAfee report said.
The Washington Post quoted security experts as saying that China was the most likely culprit because much of the intruders' targets listed by McAfee put emphasis on organizations linked to Taiwan and the International Olympic Committee (IOC) in months leading up to the 2008 Beijing games.
Earlier this year, Internet giant Google accused the Chinese government of disrupting its e-mail services inside China over a number of months, as netizens complained of inaccessible accounts and attempts to steal their passwords.
Google said in January 2010 that it had been the target of cyber-attacks that originated in China, with the Gmail accounts of rights activists affected.
The company later redirected China search-engine traffic to Hong Kong and scaled down its presence in China.
McAfee said in February that hackers working from China had targeted the computers of oil and gas companies in the U.S., Greece, Taiwan, and Kazakhstan.
The “coordinated, covert, and targeted” attacks began in November 2009, and the hackers had succeeded in stealing sensitive information, it said.
The Chinese government has denied any involvement in hacker activities, saying it is opposed to them.
Reported by Luisetta Mudie.