China's Communist Party mouthpiece on Sunday accused the United States of mounting a cyber army and a "hacker brigade", and of exploiting social media like Twitter or Youtube to foment unrest in Iran.
The People's Daily accused the United States of controlling the Internet in the name of Internet freedom after secretary of State Hillary Clinton called for more Internet freedoms in China and elsewhere in a speech on Thursday.
China on Friday warned that Washington's push against Internet censorship could harm ties.
"Behind what America calls free speech is naked political scheming. How did the unrest after the Iranian elections come about?" said the editorial, signed by Wang Xiaoyang.
"It was because online warfare launched by America, via Youtube video and Twitter microblogging, spread rumours, created splits, stirred up, and sowed discord between the followers of conservative reformist factions."
China has blocked Youtube since March, the anniversary of uprisings in Tibet, and Twitter since June, just before the 20th anniversary of a crackdown on protestors in and near Tiananmen Square. Facebook has been down since early July.
The People's Daily editorial asked rhetorically if obscene information or activities promoting terrorism would be allowed on the Internet in the US.
"We're afraid that in the eyes of American politicians, only information controlled by America is free information, only news acknowledged by America is free news, only speech approved by America is free speech, and only information flow that suits American interests is free information flow," it said.
Clinton's speech came shortly after Google revealed a sophisticated hacking attack, and said it might close its google.cn Chinese search engine if it could not find a way to offer a legal, unfiltered search service in China.
"Everyone with technical knowledge of computers knows that just because a hacker used an IP address in China, the attack was not necessarily launched by a Chinese hacker," Zhou Yonglin, deputy operations director of the National Computer Network Emergency Response Technical Team, said in an interview carried in a number of Chinese newspapers on Sunday.
Zhou mentioned an outage suffered by Chinese search engine Baidu on January 12 but did not mention that it was attacked by the Iranian Cyber Army, which had previously attacked Twitter, nor that Chinese hackers launched retaliatory attacks on Iranian sites the next day.
The People's Daily also denounced a May ban on Microsoft's instant messaging services to nations covered by US sanctions, including Cuba, Iran, Syria, Sudan and North Korea, as violating the US stated desire for free information flow.