Cambodian police barred Hollywood actress Mia Farrow and other activists from laying flowers at a "Killing Fields" museum on Sunday, as part of a campaign to end atrocities in Sudan's Darfur.
Some 100 baton-wielding police blocked Farrow, who fronts the Dream for Darfur pressure group, and her fellow activists from entering the compound at Tuol Sleng, the Phnom Penh high school that became Pol Pot's main torture center.
"Darfur has nothing to do with Cambodia. Go protest in Darfur," Phnom Penh police chief Touch Naruth told reporters after the brief stand-off ended without incident.
Other similar events
The group, which had planned to light a symbolic Olympic torch in the compound, has held similar events in Chad, Rwanda, Armenia, Germany and Bosnia as part of a campaign to persuade China to push Khartoum into ending the violence in Darfur.
The group, which included a survivor of the Rwandan genocide, were due to hold a press conference later in the day.
Beijing is hosting the 2008 Olympic Games and human rights groups have targeted China in the hope of using the spotlight thrown on the country to influence Chinese foreign policy.
China, a major investor in Sudan's oil industry, has been accused of breaching international rules and fanning bloodshed by selling Sudan weapons that have been diverted to Darfur.
International experts estimate 200,000 people have died and 2.5 million others have been driven from their homes in years of fighting. The Sudanese authorities put the death toll at 9,000 and say the West has exaggerated the conflict.
Farrow said in an earlier interview that Phnom Penh was putting the interests of Beijing, one of its biggest donors, above the memories of the estimated 1.7 million victims of Pol Pot's 1975-79 reign of terror.
"We came here with the deepest respect," Farrow told Reuters, tears welling up in her eyes. "I am sad because I think it's a good thing to do."
Cambodian government spokesman Khieu Khanarith had said Farrow's group would face "consequences," including possible deportation, if it pushed ahead with its plans.
"What they will be doing at Tuol Sleng is not to commemorate the victims of the Khmer Rouge, but to use Khmer skulls to pressure China. This is an insult to the Cambodian people," he told Reuters.
The U.S. actress called on China to use its influence to push Khartoum to halt the violence in its western Darfur region and admit international peace-keepers.
"Please, China, do everything in your considerable power to persuade Khartoum to admit the peacekeeping force," she said.
"They can effectively provide security for the people of Darfur and the innocent civilian population that is being ripped apart."