In Ankara, the Turkish capital, a member of China's Uighur minority drenched himself in gasoline and set himself on fire before fellow demonstrators rushed to extinguish the flames and took him to a hospital.
Thousands of exiled Tibetans took their grievances to the streets in Nepal and India. Demonstrations of one size or another also took place in London, Madrid, Berlin, Stockholm, Lisbon, Amsterdam and New York, with further marches planned in Washington and Toronto.
The Olympic Games have furnished a kind of soapbox for a strikingly diverse array of rights groups. Like protesters in the spring during the Olympic torch's disrupted passage across the world, activists on Friday demonstrated on issues including China's human rights record, more autonomy for Tibet and rights for religious minorities.
Typical was the protest in Paris outside a heavily guarded Chinese Embassy, where Reporters Without Borders, an advocacy group of journalists that focuses on press freedom, demonstrated alongside Amnesty International, campaigners for Tibet and proponents of independence for the Uighurs, a Muslim minority in western China.
Illustrating the unease that such protests have set off in some Western countries, the Paris police initially banned the demonstration. A judge later overturned the ban.
The effort that received perhaps the most attention, however, was in Beijing itself, where Reporters Without Borders pirated a radio frequency and broadcast criticisms of China in Mandarin, French and English.
The 20-minute broadcast began around 8 a.m., 12 hours before the Olympics' opening ceremonies. Using miniature FM transmitters and antennas, Robert MÃƒ©nard, head of the group, and a number of Chinese dissidents called for free speech and worldwide demonstrations during the ceremonies.
"This is the first nonstate radio broadcast in China since the Communist Party took power in 1949," Mr. MÃƒ©nard said. "We lost the battle for a boycott of the opening ceremony, but that does not mean that we will keep quiet."
Meanwhile, Students for a Free Tibet, an advocacy group with more than 650 chapters in about 30 countries, said three Americans had been detained after trying to protest near the site of the opening ceremonies in Beijing, The Associated Press reported. The police did not immediately confirm the detentions.
In Hong Kong, several protests were organized, but nothing like the crowds of tens of thousands here who still commemorate the Tiananmen Square killings each June 4.
A lone British activist, dubbed Spiderman by the local news media, scaled a bridge and hung a banner that read, "The People of China Want Freedom From Oppression." The police removed the banner, and the man was detained.
Several groups organized a small demonstration outside the site in Hong Kong where Olympic dressage and show-jumping events will be held over the next two weeks.
"We are protesting against the Chinese government's failure to live up to the undertakings it made seven years ago, when it made its bid to host the Olympics," said Emily Lau, a member of Hong Kong's Legislative Council who is also the leader of the Frontier, a small political group. She called on officials in Beijing to release all political prisoners. Ms. Lau said that 120 to 150 people participated in the demonstration; the police did not provide an estimate.
As the opening ceremonies were broadcast against an outdoor wall of the Hong Kong Cultural Center, uniformed police officers were in evidence but not in large numbers. Many people stayed home because of rain lingering after a severe tropical storm, Kammuri, brushed by Hong Kong on Wednesday. But the skies parted and the stars came out shortly before the broadcast began.
Hong Kong immigration officials denied entry this week to three human rights activists, at least one of whom was planning a peaceful protest during the Olympics.
Steve Vickers, a former head of criminal intelligence in Hong Kong, said the risk of terrorist attacks at Olympic venues in Beijing and elsewhere was "medium to low" because of a heavy security presence. But Mr. Vickers, now the chief executive of International Risk, an Asian security consulting firm, predicted that publicity stunts and peaceful demonstrations were likely to continue during the Olympics, especially in Hong Kong.
In Katmandu, Nepal, the police arrested more than 1,000 people who defied a ban on protests to gather outside the visa office of the Chinese Embassy, The A.P. reported.
In New Delhi, almost 3,000 Tibetans chanting anti-China slogans marched outside the Indian Parliament, and a group of monks tried to storm the Chinese Embassy during the opening ceremonies. About 2,000 more marched in the Indian city of Dharamsala, where the exiled Tibetan leadership is based.
In Brussels, hundreds of protesters turned out. Five of them stood outside the European Union headquarters sporting Olympic rings around their necks and chains around their wrists.
According to Daniel Cohn-Bendit, the celebrated leader of the 1968 student protests in France and now co-president of the Green Party in the European Parliament, the demonstrations worldwide signified a solidarity with activists in China.
"If we talk more about human rights in China today it is because of protests like this," Mr. Cohn-Bendit said. "Noise is good."
In Lower Manhattan, a small but symbolic gesture unfolded while a street entertainer played "America the Beautiful" on a steel drum and hundreds of sightseers lined up in Battery Park to board the ferry to the Statue of Liberty.
Very few noticed an airplane circling the statue, towing a banner that read, "Red Torch for Tibet." The letters were difficult to make out from the dock, where most people seemed busy taking pictures and keeping up with the line.
When the plane was pointed out, Jesse Bluma, 33, of Orange County, Calif., said: "It's a complicated issue. Do we support our athletes who've worked so hard to get there? Or do we speak out against the place that doesn't really honor our freedom and achievements?"
Katrin Bennhold reported from Paris, and Keith Bradsher from Hong Kong. David Giambusso contributed reporting from New York.
Copyright 2008 The New York Times Company