"The Tibetans continue to try and protest in small groups and as long as they keep coming we will detain them," a senior police officer said.
"The total number of detainees has reached 1,100. They are being held at various police stations and will be released later on Friday."
Some protesters scuffled with police, who kicked and hit the Tibetans with bamboo poles as they tried to break through the police cordon.
Other protesters shaved their heads and painted their faces and scalps with the flag of the Tibetan government-in-exile. They also wore headbands calling for a "Free Tibet".
Authorities in China are on their highest alert in the final hours before the opening ceremony of the Beijing Olympics, guarding against anyone who might try to take the shine off the curtain raiser that would be watched worldwide.
Tiananmen Square was sealed off. Many foreigners who were detained after protesting have been deported, and Chinese who did the same were in custody.
Aug 4 - Separatists group allegedly kill 16 police in China's far-west Xinjiang region, an attack the government said was aimed at disrupting the Games.
Aug 5 - US speedskater and Olympic gold medallist Joey Cheek, co-founder of Team Darfur group of athletes that campaigns for an end to the crisis in Sudan's Darfur region, says China has revoked his visa, so he will not attend the games.
Aug 6 - Four foreign Tibet activists scale power poles near the Bird's Nest National Stadium and unfurl Tibet independence banners, as the Olympic torch makes its way through the streets of Beijing.
- Three prominent Chinese activists are blocked from entering Hong Kong, the venue for Olympic equestrian events.
- A small group of US Christians stage a brief protest for religious freedom on Beijing's central Tiananmen Square before being briefly detained.
Aug 7 - About 2,000 Tibetans and their Nepali supporters take part in peaceful protests in Kathmandu, calling for the
release of Tibetan monks and nuns jailed in China.
Aug 8 - Paris-based press watchdog Reporters Without Borders broadcasts an on-air challenge to China's censors and
urge the release of political prisoners.
- In Hong Kong, a lone protester unfurls banners calling for respect for human rights in China on the southern city's largest suspension bridge.
In Hong Kong, a British man was arrested on Friday after climbing on to the city's largest bridge and unfurling two protest banners.
Matt Pearce, 33, climbed on to a narrow girder in the centre of the bridge wearing a horse costume - alluding to the Olympic equestrian events being held in Hong Kong - and carrying a guitar, a witness said.
The large red banners read: "The People of China want freedom from oppression" and "We want human rights and
Police closed the bridge to traffic and set up a giant inflatable safety mattress beneath the girder before climbing after Pearce and arresting him.
Hong Kong enjoys much greater freedoms than mainland China, including the right to protest.
However, three prominent Chinese activists were blocked from entering Hong Kong on Wednesday amid a tightening of the city's immigration and security measures days before Olympic equestrian events.
Protests set to coincide with the opening ceremony of the Beijing games are due to take place in London, Paris and Berlin. Rallies were held in Australia and planned in the Philippines and India.
Exiled Tibetans have been protesting virtually daily after deadly unrest erupted against Chinese rule in the Himalayan region in March.
On Thursday, around 600 Tibetans were arrested in Kathmandu, several hours after 1,500 monks, nuns and supporters who had been praying and chanting mantras refused to disperse.
Nepalese officials have repeatedly said no anti-China activity will be allowed as they seek to preserve friendly ties with their giant northern neighbour.
The country is home to about 20,000 exiled Tibetans who began arriving in large numbers in 1959 after the Dalai Lama, the Tibetan spiritual leader, fled Tibet following a failed uprising against the Chinese.