'Sites blocked' ahead of web summit
Chinese censors have blocked access to several popular websites as they target content delivery networks that serve much of the internet, according to a US internet service company.
The action comes as China hosts the World Internet Conference, which brings together many of the world's top technology companies.
EdgeCast, an affiliate of Verizon, said censors have taken down several networks that provide local servers to help speed up website performance.
EdgeCast provides such a network, and its clients include software company Mozilla, publishing company The Atlantic and content management system Drupal.
The online activist group Greatfire.org said it was the target of the Chinese action, which blocked many other sites that use EdgeCast.
The group enables Chinese internet users to access websites otherwise blocked by Chinese censors. EdgeCast did not confirm Greatfire.org's statement.
A Greatfire.org co-founder, who goes by the pseudonym Charlie Smith, said they had chosen to use several content delivery networks knowing that any move to take down their site would affect others.
"We knew that ahead of time," he said. "It was our feeling that the authorities would not take that kind of action."
China employs thousands of censors who block hundreds of websites and erase social media messages dealing with sensitive political topics. At the same time, it claims some of the world's most popular online sites, including e-commerce giant Alibaba.
Alibaba founder Jack Ma told the Internet conference Wednesday that China's online strength is bound to transform the Web.
Outside the conference hall, several protesters were detained after holding up a banner demanding that China allow access to sites such as Google, Facebook and Twitter.
Mr Ma told the conference: "I believe China's Internet is not only profoundly influencing aspects of China's economic development but is also participating in the development of the Internet across the world."