A new law in Xinjiang makes it a criminal offence to produce or spread information that could jeopardise ethnic solidarity.
The law, which was ratified by the region's top legislative body yesterday and is the first regional-level law of its kind, comes nearly six months after clashes between Uygur and Han Chinese in Urumqi left at least 197 people dead and nearly 2,000 injured.
Highlighting separatism as the major threat to stability in the region, the law says intensifying ethnic unity and safeguarding national solidarity is the 'sacred duty and glorious obligation for each citizen in Xinjiang', the China News Service reported.
The law bans organisations or individuals from disseminating opinion and information that are unfavourable to stability, as well as any other action that might endanger ethnic unity or promote separatism.
Professor Ong Yew-kim, a Hong Kong-based professor at the China University of Political Science and Law, said the law was too vague to be enforced.
'The definition of 'unfavourable to' or 'jeopardising' ethnic unity is far from clear for the law to be enforced properly,' he said. 'The regional legislature has to introduce a legal interpretation before its implementation, or it may be interpreted differently from one law enforcer to another.'
Ong suggested political concerns might have spurred the drafting and adoption of the law.
'So far, the Xinjiang regional authority has brought no effective measure to settle the ethnic conflicts and narrow the discrepancy - on an economic, social and cultural basis - between the Uygur minority and Han majority,' he said.
'This kind of law may largely be aimed at silencing the voicing of disappointment.'
Meanwhile, Xinhua reported that three men were detained last Tuesday by police in Guangzhou for fabricating an online article saying several Uygurs were beaten up by local people and security guards on suspicion of stealing.
The central government and Xinjiang authorities have dismissed suggestions that ethnic policies played a part in the unrest.
An uneasy calm has returned to Urumqi after July's riots and a wave of syringe attacks in August and September. But tensions between the Hans and Uygurs remain.