The Dalai Lama has said he fears there will be more deaths in Tibet unless Beijing changes its policies towards the Chinese-controlled region.
The Tibetan spiritual leader told the BBC he had "grave concerns" over Friday's deadly protests in Lhasa city.
But he emphasised that he still supported Beijing's staging of the Olympic Games this summer.
Lhasa, Tibet's main city, was reported quiet on Sunday, locked down by a heavy Chinese security presence.
The Dalai Lama told the BBC he had received reports the death toll from the protests may be as high as 100, although he said the figure could not be verified.
The Chinese official news agency Xinhua says 10 people died in Friday's clashes, including business people it said were "burnt to death".
On Sunday, businesses remained shut, the streets were empty and locals said a curfew was in force.
The unrest erupted a fortnight before China's Olympic celebrations kick off with the start of the torch relay, which is scheduled to pass through Tibet.
The Dalai Lama told the BBC the Games were an opportunity for the Chinese to show their support for the principle of freedom.
The demonstrators, who on Friday set fire to Chinese-owed shops and hurled rocks at local police, have been penned into an area of the old town by government forces.
A government official in Lhasa told AP news agency: "It is fairly quiet this morning (Sunday). The local people have been persuaded not to go out."
A shopkeeper in the city told Reuters news agency: "There are police checking our homes and handing out warnings."
Eyewitnesses described seeing military checkpoints, with vehicles and armed troops patrolling the streets.
A 23-year-old Canadian student told AP: "The entire city is basically closed down."
US Secretary of State Condoleezza Rice on Saturday urged China to "exercise restraint" in dealing with the protests.
She spoke as pro-Tibet demonstrations were held in Nepal, New York, Australia and several European cities.
A British journalist in Lhasa on Saturday said police had used tear gas to disperse demonstrators defying a curfew.
The authorities in Tibet have urged the protesters to hand themselves in by midnight on Monday, promising leniency to those who surrender.
The violence - the worst in Tibet since 1989 - erupted on the fifth day of largely peaceful protests that began on last Monday's anniversary of a 1959 uprising against Chinese rule.
The demonstrations - like those last September in Burma - were initially led by Buddhist monks and then attracted crowds of ordinary people.
Chinese officials said the riots had been "masterminded" by the Dalai Lama, an accusation he has denied.
Analysts say the last thing Beijing wants is bloodshed tarnishing its image before it stages the Olympic Games in August, but at the same time it cannot show weakness to the protesters.
Many Tibetans claim their culture has been brushed aside by Beijing and resent local Chinese settlers.
China says Tibet has always been part of its territory, although Tibet enjoyed long periods of autonomy before the 20th Century.