"Yanhuang Chunqiu" (China Through the Ages) is an influential Beijing magazine that features essays from reformist retired officials.

In a message posted on its official Sina Weibo microblog, the magazine said that it had been informed on Thursday that the site's registration had been canceled and that it had not been given a reason.

"The magazine is trying to find out details," it said.

Attempts to open the website (www.yhcqw.com) bring up a cartoon picture of a policemen holding up a badge and the message that the site has been closed.

However, the article which seems to have offended the censors, written in the form of a new year's message, is still up on the magazine's microblog.

"In more than 30 years of reform, the abuses caused by political reform lagging economic reform have become daily more visible, and the factors for social instability have gradually accumulated. Promoting reform of the political system is an urgent task," the piece says.

Weibo users flocked to offer their support for the magazine and to excoriate Xi.

"People who are putting their hopes in Xi need to wake up," wrote one.

Xi, who became party boss in November, takes over from Hu Jintao as president at the annual meeting of parliament in March, part of a generational leadership change.

Last month, a prominent group of Chinese academics warned in a bold open letter that the country risks "violent revolution" if the government does not respond to public pressure and allow long-stalled political reforms.