Chinese authorities have taken over computers both inside and outside the country to launch cyberattacks against the website of an anti-online censorship group and a U.S.-based Web resource that hosts some of the group's data, according to an analysis released by the group.

Greatfire.org said in a statement Monday that Chinese authorities carried out denial-of-service attacks that have intermittently shut down San Francisco-based Github over the past week. Greatfire.org said it had mirrored some of its content on Github repositories, and that the data were the targets of the attacks.

Greatfire.org said Chinese authorities carried out the attacks by installing malicious code on the computers of users visiting the popular Chinese search engine Baidu and related sites and using those computers to overwhelm Github and Greatfire.org websites with service requests.

The group said the attacks marked the first of their kind blamed on Chinese authorities and represented a dangerous escalation for a country that already tightly restricts what Chinese can see online. Greatfire.org said it was a direct target of similar denial-of-service attacks earlier in March.

Greatfire.org produces mirror websites that let Chinese users see information normally blocked by government censors. The group doesn't reveal where it's located or who runs it. The Open Technology Fund, a U.S. government-backed initiative to support Internet freedom, says on its website that it provided Greatfire.org with $114,000 in 2014.

The Cyberspace Administration of China didn't respond to requests for comment Tuesday.

"Very clearly, the Cyberspace Administration of China is behind both of the recent (distributed denial-of-service) attacks," Greatfire.org said in its statement. "Hijacking the computers of millions of innocent internet users around the world is particularly striking as it illustrates the utter disregard the Chinese authorities have for international as well as even Chinese internet governance norms."