Chinese police in the capital of Tibet have detained at least 81 people in thousands of raids in a crackdown ostensibly aimed at crime, dissidents said.

Supporters of Tibetan independence say the "strike hard" campaign was actually aimed at their movement, the China Post reported. At least two of the detainees were picked up for having "reactionary" cell phone ring tones.

The Lhasa Evening News said more than 600 officers were involved in raids on 2,922 apartments or houses, 14 hotels and guesthouses, 18 bars and three Internet cafes. The raids began Jan. 18.

"The motive is to intimidate and eliminate those supporting Tibetan independence and human rights activists in Tibet," the Tibetan Centre for Human Rights and Democracy said in a statement.

This year marks the 50th anniversary of an uprising in March 1959 against Chinese rule of Tibet. The uprising failed and the Dalai Lama fled to India and has lived in exile ever since.

The provincial legislature, dominated by Beijing, proclaimed March 28 this year as a new holiday to celebrate the liberation of Tibetan serfs from feudalism.