Footage apparently army-labeled software feature raises questions about China 's denials of involvement in hacking

China 's state radio has shown footage clearly marked with army software for the attack on U.S. websites, say security experts.

Beijing has consistently denied claims that China has been behind cyber-attacks, insisting that it plays no part in hacking and is itself a victim.

The analysts cautioned that the six-second clip could be a mock-up by the broadcaster, CCTV, and that, if genuine, it was probably around 10 years old. Either way, it is in marked contrast to China's usual stance on the issue.

The pictures were taken when the Pentagon 's Annual Report to Congress on the Chinese military said the People' s Liberation Army (PLA) had some important technological gaps and was on the right path for modernization by 2020, including through investments in cyber-capabilities. China 's state news agency Xinhua denounced the document as scaremongering "Cock and Bull Story".

The CCTV footage showed was part of a cyber-documentary about their military channel screened last month - and from its website after U.S. security experts wrote.

The programme includes a detailed discussion of cybersecurity by Senior Colonel Du Wenlong of the PLA's academy of military sciences.

A narrator then be operated methods of attack as the screen shows an invisible software users.

The Chinese characters indicate an option for a distributed denial of service attack, a crude form of attack which disrupts access to a site by bombarding it with requests for data.

Another picture shows the words "attack system" and "PLA Electronic Engineering Institute" on the screen. The user selects a name - minghui.org - from a list of sites from the banned Falun Gong spiritual movement and clicks on a button to check your "attack".

The safety of China-focused guide site hit the shots, if real, probably more than a decade had become old, because the method was so simple and there are several such attacks on Falun Gong websites in the years 1999 and 2000.

Dr. Andrew Erickson, an associate professor at the U.S. Naval War College 's China Maritime Studies Institute and Gabe Collins, a commodity and security specialist, wrote: "It seemed from the computer screen shots of a Chinese military academy will show a rudimentary kind of cyber-attack against a U.S. based dissident unit, however modest, ambiguous -. and from China 's perspective, defensive - this is perhaps the first direct piece of visual evidence from an official Chinese government to undermine Beijing source' s official claims never to engage in overseas hacking of any kind for public purposes. "

Had scoffed when asked whether the material was said CCTV 7 is not to respond to inquiries from foreign media. CCTV has caught using misleading footage in the past - memorably in January, when the shots from the movie Top Gun in a news report on PLA exercises were added.

The Foreign Ministry in Beijing do not respond to requests.

The Washington Post, said Wang Baodong, a spokesman for the Chinese Embassy in Washington, declined to comment on the video, but added: "It 's no secret that Falun Gong has been intensifying its subordinate institutions and their subversive efforts against China in cyberspace. And China has every legitimate right to take against such harmful activities to its national security interests. "Cyber ??attacks are increasingly defending a source of concern for governments around the world. The Pentagon said in a policy paper early this year that they would be willing to use conventional military action to take revenge against them.

Earlier this month, claimed that security company McAfee had the greatest series of cyber attacks so far discovered, and believed that a state was responsible actors. Security experts suggested that probably in China. Last year, the PLA has announced that it set up a special command, to handle cyber-threats, but said that the department were used for defensive purposes. The US-created a similar center in 2009.

The U.S. and Israel are also widely believed that the responsibility for the Stuxnet virus, which allegedly interfered Iran 's nuclear program have.