Capital authorities have announced a sweeping ban on all non-official posters and slogans, tightening a stranglehold on free expression imposed following last year's crackdown on the democracy movement.

The 11-point regulation forbidding unauthorized displays of slogans and propaganda was carried in the state-run Beijing Legal Daily and reportedly took effect Sept. 1.No reason was given for the delay in announcing the measures.

The rules announced Wednesday are the latest in a series of restrictive government measures enacted in the past 18 months that severely curb constitutionally guaranteed rights of free expression.

China's 1982 constitution guarantees the right of speech and assembly but omits an earlier freedom to put up "big character posters," a traditional Chinese method of expressing dissent.

Earlier this year, the government issued strict rules barring unauthorized demonstrations, rallies or congregations in and around Tiananmen Square and major avenues throughout Beijing.

The precautions are intended to deter would-be protesters from taking to the streets in a repeat of last year's tumultuous democracy protests, but they appear to be largely a formality because the cowed populace has made no overt sign of protest since the crackdown and public displays of dissent are rare.

Under the new rules, any individual or work unit wishing to display a banner or propaganda poster other than those ordered by the government must submit a detailed petition to the local bureau of public health and environment.

Special permission from the Beijing city government and the State Council, China's Cabinet, is required to raise slogans in the politically sensitive area of Tiananmen Square and environs.

In addition to Tiananmen, the new regulations include a vague catch-all stipulating only that "other areas designated by the city government" also require special permission for the display of unofficial slogans.

Those who violate the new rules may be fined up to $96, more than three months' wages for the average worker.