There has been a steady security build-up in Tibetan areas
Chinese authorities have issued a list of 21 people wanted for their alleged role in anti-China riots in the Tibetan city of Lhasa last week.
Photos of the suspects were posted on the internet as China continued the crackdown that followed the unrest.
China has said that 19 people were killed in the Lhasa riots, which later spread to other Tibetan areas.
But Tibetan exiles say that nearly 100 have been killed by the Chinese security forces.
The official People's Daily newspaper said on Saturday that those responsible should be severely punished.
"China must resolutely crush the conspiracy of sabotage and smash 'Tibet independence forces'," the paper said in an editorial.
In posting photos of suspects, authorities offered rewards and anonymity to those who helped.
The official Xinhua news agency said that two of the 21 suspects had already been arrested and a third had turned himself in.
The unrest began on 10 March in Lhasa and gradually escalated, spreading to Tibetan communities in neighbouring Gansu, Sichuan and Qinghai provinces.
Tibet: Protests began in Lhasa on 10 March, dozens reported dead over weekend
Gansu: Unrest spread to Machu, where Tibetan government in exile says 19 died, and near Hezuo, where protesters were filmed tearing down Chinese flag
Sichuan: State media says four people 'shot and wounded' by police in Aba
Qinghai: Other unrest reported
A week after the initial riots, estimates of how many people were killed and accounts of who was to blame differed wildly.
China says 18 civilians and a policeman were killed and hundreds injured.
But the Tibetan government-in-exile says at least 99 people have died in the crackdown by Chinese troops.
During the clampdown, troops have sealed off towns in the surrounding areas where unrest has taken place, according to witnesses. Authorities are not allowing foreign journalists into Tibet.
Other witnesses have reported seeing hundreds of troop carriers heading for Tibetan areas in recent days.
In Gansu, public notices and police broadcasts told protesters to surrender by midnight on 25 March or face arrest and punishment.
On Thursday Chinese authorities admitted for the first time that members of the security forces had fired on Tibetan protesters, wounding four protesters last Sunday in Aba county, Sichuan.
Tibetan sources say at least eight people were killed in the demonstration.
Beijing has largely ignored international calls for dialogue with the Dalai Lama, regarded by many Tibetans as their spiritual leader.
Chinese authorities have blamed the Dalai Lama for orchestrating the unrest in an attempt to sabotage this summer's Beijing Olympics and promote Tibetan independence.
The Dalai Lama has criticised the violence.
He has stressed that he is seeking autonomy not independence and has called for talks with Chinese President Hu Jintao.
On Friday the Speaker of the US House of Representatives, Nancy Pelosi, called for an independent investigation into China's claims that the Dalai Lama instigated the violence in Tibet.
Speaking while visiting the Dalai Lama in northern India, she also called on the international community to denounce Chinese rule in Tibet.