BEIJING — Beijing is braced for demonstrations today when the Olympic torch arrives in China after protesters once again disrupted Olympic ceremonies in Greece. Security will be tighter than normal in Tiananmen Square — where pro-democracy protests in 1989 were crushed by force — for a ceremony to welcome the Olympic flame.

The torch will then leave on a four-month relay around the world, including stops in Tibet.

Protests in the Tibetan capital, Lhasa, earlier this month against Chinese rule escalated into widespread rioting, which then spread to neighboring Chinese provinces populated by Tibetans.

Beijing says rioters killed 18 civilians and two police officers. Exiled Tibetan leaders have put the death toll from the Chinese crackdown at 135–140 Tibetans, with another 1,000 injured and many detained.

Yesterday, pro-Tibet campaigners disrupted the ceremony in Athens at which the Olympic flame was passed to Liu Qi, the head of the Beijing organizing committee.

A small group of protesters were arrested as they tried to unfurl a banner that read “Stop genocide in Tibet.” They shouted slogans instead.

More than 2,000 police were on duty to prevent a repeat of the scenes last week when three members of the press freedom group Reporters Without Borders disrupted the flame-lighting ceremony at Olympia.

Beijing attempted to regain the initiative yesterday in the debate over Tibet’s status by accusing the “Dalai Lama clique” of refusing to discuss its future.

State press and broadcast outlets also claimed that a Tibetan arrested in Lhasa had “confessed” to orchestrating protests on behalf of the Tibetan government-in-exile.

“For the sake of protecting myself, [the Dalai Lama clique] asked me not to participate in the demonstrations in person, just be in charge of stirring people up,” the suspect was quoted as saying, without saying how he came to repent so quickly.

“The beating, smashing, looting, and burning were by no means peaceful demonstrations, and the deeds were inhuman. If they wanted to follow the nonviolence ‘middle way,’ such violence should have never happened.”

Sporadic unrest in Tibet was still being reported yesterday by the government-in-exile and support groups overseas. According to one account, there was a fracas in central Lhasa on Saturday afternoon amid a security check by police on identity papers.

That occurred shortly after a group of 14 foreign diplomats based in Beijing was given a guided tour of the city. They were taken to shops and schools set on fire in anti-Chinese ethnic unrest on March 14, and interviewed those injured.