BEIJING - A new protest broke out in a restive Tibetan region of western China, prompting wide-scale arrests and tightened security, local hotel workers and an activist group reported Friday.

More than 100 ethnic Tibetans, including Buddhist monks and lay people, were detained following the protest Thursday in Tongren county in Qinghai province, the Tibetan Center for Human Rights and Democracy reported.

Monks calling for the release of fellow Buddhist clergy were joined Thursday by local residents at a market, according to the centre, based in the Indian town of Dharmsala, the seat of the Tibetan government-in-exile. It said police rushed to the scene and began beating participants, despite efforts at mediation by a senior monk.

Receptionists reached by phone at Tongren hotels confirmed the protest, saying a crowd had gathered near the local county offices.

"Today there's no more protests. Those people were all seized," one receptionist said.

A woman at another hotel put the number of protesters in the dozens and said the local monastery of Rongwo had been closed to visitors.

Police and armed paramilitary police were checking identification cards and residency permits and imposed an overnight curfew, she said.

"Police even came to our hotel to check on people. No one was allowed outside after 12 p.m.," she said. The women refused to give their names for fear of retaliation by authorities, who have reportedly offered rewards for information on people leaking news of protests and crackdowns to the outside.

A worker at a Tibetan restaurant in downtown Tongren near the monastery said police attacked protesters indiscriminately.

"They were randomly beating people," said the woman, who gave her name as Duoma.

She said the monastery was completely sealed off Friday, with no one allowed to enter or leave.

Monks had originally demanded the release of those detained after a March 16 protest, in which about 100 monks climbed a hillside above the monastery, burned incense and set off fireworks, while riot police massed outside.

Tongren, located in a valley 1,000 kilometres north of the Tibetan capital of Lhasa, is a mix of Tibetans and ethnic Han Chinese.

Anti-government protests sprung up throughout Tibetan areas of western China after demonstrations in Lhasa turned violent on March 14. Hundreds of shops were torched and mobs attacked Han Chinese.

State media have reported more than 3,000 people either answered calls to surrender to police or have been captured, with at least 1,870 released because they committed only minor offences.

Beijing has blamed the violence on the exiled Tibetan spiritual leader the Dalai Lama and his supporters, and said 22 people died in the Lhasa rioting.

The Dalai Lama's Tibetan government-in-exile says more than 140 people were killed in the government crackdown.