The Beijing Olympic torch was due to be lit in Greece on Monday but celebrations were at risk of being overshadowed by China's controversial efforts to quell two weeks of deadly Tibetan unrest.
The Chinese military was maintaining a lockdown on Monday of Tibet and nearby provinces where protests have taken place over China's 57-year rule of the remote Himalayan region.
Beijing had repeatedly insisted that exiled Tibetan spiritual leader the Dalai Lama is masterminding the protests, which officially have left 19 people dead, and that the unrest is a deliberate campaign to sabotage the Games.
The Olympics were set to be drawn more closely into the controversy on Monday, with the torch for this August's Games to be lit in Olympia in southwestern Greece where the ancient Olympics were born in 776 BC.
The Olympic flame is scheduled to pass over Mount Everest in Tibet in early May, and through the region's capital of Lhasa, the scene of the most violent protests, the following month.
The lighting of the flame will trigger a wave of global protests against Chinese authorities over Tibet and a range of other issues, such as China's record on human rights and religious freedoms, activists groups told AFP.
Amid calls by some activists for a boycott of the Games due to Tibet, International Olympic Committee chief Jacques Rogge on Sunday reiterated the IOC's position that the Games would be a positive factor for change in China.
"The events in Tibet are a matter of great concern to the IOC... but we are neither a political nor an activist organisation," Rogge said in a statement.
"We believe that China will change by opening the country to the scrutiny of the world through the 25,000 media who will attend the Games."
In China, the communist authorities are continuing to try to prevent independent accounts of the unrest, which the Tibetan government-in-exile said last week had left at least 99 people dead.
Foreign reporters remained banned from entering Lhasa, where Buddhist monks began the protests on March 10 to mark the anniversary of a failed 1959 uprising against China's rule of Tibet.
China has also kept a tight lid across a huge swathe of regions bordering and nearby Tibet where protests by ethnic Tibetans have taken place, with a heavy security presence denying foreign reporters access.
An AFP reporter in western Sichuan province who saw a huge military presence in the area on Sunday was prevented from moving out of the town of Kangding into Tibetan-populated regions on Monday.
A day earlier, the AFP reporter had travelled up into the now blocked regions, seeing more than 100 military vehicles, at least two military camps and dozens of police cars swarming the remote, mountainous area.
The region is just outside the Garze Tibetan Autonomous Region and about 200 kilometres (120 miles) south of Ngawa county, where Buddhist monks and other Tibetans had clashed with police.
In neighbouring Qinghai province a AFP reporter on Sunday was turned back at a police checkpoint while trying to reach the town of Tongren, site of an important Tibetan Buddhist monastery where similar protests had been reported.
Due to the restrictions, it has been difficult for foreign reporters to get an accurate picture of what is occurring in these areas, but activist groups reported sporadic protests over the weekend in Qinghai and Gansu provinces.
The Free Tibet Campaign, citing an eyewitness, said around 200 monks and 800 lay Tibetans marched 25 kilometres to the Lhushue Choryithang monastery, Gansu, on Saturday chanting for the return of the Dalai Lama and for a free Tibet.
The statement said that many of the monks and lay people had fled into the mountains fearing arrest by the authorities. (AFP)
Tibetan protests threaten to overshadow Olympic flame ceremony