LONDON, Aug 30 (AFP) - Chinese authorities arrested up to 25 monks and closed a school at a monastery in Taersi, in China's far west, after pro-Tibetan independence posters and leaflets were distributed at the site, the Tibet Information Network (TIN) reported Friday.

The student monks were detained for six weeks from mid-March to early May in Taersi, which Tibetans call Kumbum and which is the main Buddhist site in the Chinese province of Qinghai, the former east Tibetan region of Amdo, said the London-based group, which monitors Tibetan affairs.

One student was in a coma when he was released in April, apparently as a result of being tortured during police questioning about the posters, TIN said, adding that four monks were still in custody after five months.

A further 100 monks were reportedly expelled from the monastery.

The order to close the monastery's school was issued on May 6 by the Qinghai provincial government, according to "unofficial sources" quoted by TIN.

The four monks still in police custody have been accused of producing the posters and leaflets which contain prayers for the child recognised last year by the Dalai Lama, Tibet's spiritual leader in exile, as the reincarnation of the Panchen Lama, who ranks second in the Tibetan Buddhist hierarchy.

Beijing turned down the Dalai Lama's choice of candidate, and enthroned a rival candidate, a boy approved by the central government, in December last year.

The Dalai Lama, awarded the Nobel Peace Prize in 1989, went into exile in India in 1959 after the bloody suppression of an anti-Chinese uprising.

China's communist armies moved into Tibet in 1950. Critics of its rule there say that continued migration by Chinese threatens to overwhelm the native culture of around six million Tibetans.