Spontaneous mass rallies and demonstrations have been banned in the area within the ancient city wall built in Ming Dynasty (1368-1644), the Xi'an Public Security Bureau announced on Sunday night.

The bureau made the announcement on the local TV station arround 8:00 pm on Sunday.

The bureau said that during recent spontaneous demonstrations against Japan's "purchase" of the Diaoyu Islands, irrational and even the illegal activities had occurred, including damaging of public and private property, seriously affecting the social order.

To maintain order, the bureau required that anyone who wants to hold mass rally or demonstration must apply for a permit from the bureau, in accordance with the law, and such activities cannot be held without the bureau's approval.

Mass public events have been banned within the area of the ancient city wall, the downtown of Xi'an, capital of Shaanxi province, because a large number of malls, shops, residential communities and government buildings are concentrated there.

On Sept 15, several thousands of residents and university students held a march in downtown streets to protest the Japanese government's "purchase" of China's Diaoyu Islands, and some people who joined the crowd damaged public and private property.

The bureau said that it got information about the offenders and legal action would be taken against them. The bureau also announced a hotline number for residents to provide more clues to the offenders' identity