Taking cyber attack to new and scary level, Chinese web experts have been targeting a popular US coding website.

From Thursday onwards, GitHub has been hit by distributed denial-of-service (DDoS) attacks that sent large volumes of web traffic to the site, particularly towards two Chinese anti-censorship projects hosted there. Specifically, the traffic was directed to two GitHub pages that linked to copies of websites banned in China, the experts said. One page was run by Greatfire.org, which helps Chinese users circumvent government censorship, while the other linked to a copy of the New York Times’s Chinese language website.

Greatfire.org’s GitHub page contains links to copies of 10 websites blocked in China, including an uncensored version of the popular social-media service Weibo.

Over the next few days, the attackers changed their DDoS tactics as GitHub defended the site, but as of Sunday, it appears the site was mostly working.  A GitHub service called Gists, which lets people post bits of code, was still affected, it said. On Twitter, GitHub said it continued to adapt its defenses.

The attacks appeared to focus specifically on two projects hosted on GitHub, according to a blogger who goes by the nickname of Anthr@X on a Chinese- and English-language computer security forum.

The attack on San Francisco-based GitHub Inc. points to brazenness of China’s Internet censors, who are increasingly reaching outside the country to clamp down on content they find objectionable.

GitHub services are used by programmers and major tech firms world-wide to develop software,

The modus operandi was to direct huge amounts of traffic from overseas users of Chinese search giant Baidu Inc. to GitHub, paralyzing GitHub’s website at times.

The attackers used a wide variety of methods and tactics, including new techniques “that use the web browsers of unsuspecting, uninvolved people to flood github.com with high levels of traffic,” GitHub said.

In late December, China cut off all access to Google’s Gmail service, after blocking Facebook’s Instagram app, and the phone messaging app Line.

Baidu said it wasn’t involved in the attack and its systems weren’t infiltrated. “After careful inspection by Baidu’s security engineers, we have ruled out the possibility of security problems or hacker attacks on our own products,” it said in a statement.

Though Baidu is the largest search engine in China, the attack appeared to use traffic from its users outside the country, security experts said. When a user navigated to the Baidu search engine, they said, a code was activated that sent continuous requests for data from the user’s computer to GitHub. By tapping overseas users, the hackers made the attack harder to block, because the requests to GitHub came from all over the world and looked like typical requests for information.