China's top official in Tibet has ordered local authorities to tighten control ahead of the annual Chinese parliamentary session.
Chen Quanguo, the Communist Party secretary in Tibet, urged officials to maintain comprehensive management over mobile phones and the internet.
Officials are also not allowed to take leave in the coming days.
China's parliament will meet next week and the anniversary of deadly 2008 riots in Lhasa falls on 14 March.
Officials in Tibet should "carry out prevention and control measures in full force to crush plots aiming to sabotage stability in Tibet and threaten security of the state by hostile forces and the Dalai Group," said Chen Quanguo in a written notice published in the official Tibet Daily.
"Mobile phones, the internet and other measures for the management of new media need to be fully implemented to maintain the public's interests and national security," Mr Chen said.
Monastery management officials have also been ordered to intensify their political work and guide Tibetan Buddhist monks and nuns "to be patriotic, love their religion and respect law and order".
In the notice, Mr Chen ordered officials to maintain "round the clock presence" during this period.
He has also reiterated an earlier order that officials who failed to maintain stability would be "sacked on the spot" and would face further punishment.
The order follows a series of protests and self-immolations in ethnic Tibetan areas outside Tibet.
It comes ahead of the National People's Congress, which opens in Beijing on Monday, and a fortnight before the anniversary of the Lhasa unrest that sparked off protests across the region.
China accuses the Dalai Lama of inciting separatist activities in Tibet and its neighbouring provinces - a claim the Tibetan spiritual leader denies.
China has blamed recent protests on rioters but campaign groups say those involved are protesting against Beijing's rule and a lack of religious freedom.