By THOM BEAL

BEIJING, Dec. 6 (UPI) -- Chinese authorities Wednesday enthroned a boy they chose to be Tibet's second highest ranking spritual leader after rejecting the one nominated by the dalai lama, according to a spokesman for the Tibetan religious leader.

The spokesman said the Communist authorities secretly installed 6-year-old Gyaincain Norbu as the 11th reincarnation of the panchen lama, considered by Tibetan Buddhists as the second holiest monk after the dalai lama.

The ceremony took place at the Tashilhunpo Monastery in the Tibetan city of Xigatze, the traditional seat of the panchen lamas, the dalai lama's spokesman, Tempa Tsering, said in a telephone interview from Dharamsala, India.

The dalai lama, who lives in exile in Dharamsala, has rejected Beijing's choice of Norbu as a politically motivated attempt to tighten control over Tibet, which China annexed in 1950.

The Tibetan spiritual leader says the true incarnation of the panchen lama is Geuden Choekyi Nyima, a 6-year-old boy he had named in May but who disappeared in unexplained circumstances after Beijing called the nomination invalid.

Tibetans-in-exile claim Nyima is being held either in Beijing or under house arrest in Tibet.

Both boys were born in 1989, at the same time the 10th panchen lama died.

Tibetan Buddhists believe lamas pass their souls on to a boy born when they die.

"To give their choice legitimacy, Chinese officials timed the ceremony to coincide with the Pelay Ridro, the festival of the important Tibetan goddess Lhamo," Tsering said.

The Chinese authories did no immediately confirm that the ceremony took place.

On Nov. 29, Communist Party officials had supervised the selection of the boy as the reincarnated panchen lama in a lot drawing ceremony in the Johkang Temple in the Tibetan capital Lhasa.

Beijing claims it followed the proper Tibetan Buddhist procedure in selecting the boy and that the choice was in accordance with the wishes of the 10th panchen lama.

The 10th panchen lama, had refused to join the dalai lama in exile after a failed anti-Chinese uprising in Lhasa in 1959 and was seen by many Tibetans as a lackey of the Chinese authorities.

Wednesday's controversial ceremony was held amid tight security in Tibet.

Curfews were imposed on the three largest cities -- Lhasa, Xigatse and Chamdo -- and on Dram, a town on the Nepal-Tibet border, according to sources in Lhasa.

At the border checkpoint in Dram, Chinese guards have denied entry visas to exiled Tibetans wishing to visit relatives in Tibet.

China has launched an extensive campaign to promote its choice of the panchen lama.

Tsering said the campaign has intensified to include impromptu "calls to prayer" at dozens of monasteries, during which monks are exhorted to criticize the dalai lama and accept Beijing's method of selecting lamas.

More than 300 monks from the Sera and Drepung monasteries in Lhasa walked out of such a gathering Monday to protest the presence of Buddhist officials loyal to Beijing and security agents filming the meeting, Tsering said.

Sources in Lhasa believe Chinese authorities intend to hold loyalty tests for ranking Buddhist lamas and Tibetan cadres. Those who fail to pass would be purged.

Communist Party authorities carried out similar tests and purges earlier this year in the far western province of Xinjiang, following a series of violent uprisings by militant Muslim ethnic groups.