By Jim Wolf

WASHINGTON, Oct 22 (Reuter) - China has detained a Tibetan-born Fulbright scholar on charges of spying for the Dalai Lama's exile government, the Chinese embassy said in a letter to members of Congress made public on Tuesday.

The embassy said it had learned that Ngawang Choephel, last seen in Tibet in September 1995, had been using the cover of collecting Tibetan folk songs to spy and take part in illegal separatist activities in his Himalayan homeland.

"We have learned that, funded by some Americans, Ngawang Choephel was sent by the Dalai Lama's 'government-in-exile' to Tibet, used the cover of so-called collecting Tibetan folk songs to gather sensitive intelligence and engaged in illegal separatist activities," embassy counsellor Shao Wenguang wrote.

In a letter to Bernard Sanders, an independent congressman from Vermont who was one of the moving forces behind a congressional petition on Ngawang's behalf, the embassy added that Ngawang was suspected of violating Article 4, Section 2(5) of the Chinese State Security Law, an espionage statute.

"The judicial department of the Tibetan Autonomous Region is handling his case according to law," Shao Wenguang wrote on behalf of Ambassador Li Daoyou in the October 15 letter.

Embassy officials did not respond to requests for comment on Ngawang's health and any plans to put him on trial. The State Department had no immediate comment on the case.

The International Campaign for Tibet, a Washington-based group that monitors human rights, said Ngawang had been filming a documentary about traditional Tibetan music and dance that he feared would be lost because of alleged Chinese efforts to swamp Tibetan culture. He was arrested in a market in Shigatse, Tibet, on or about September 15, 1995.

China frequently accuses the Dalai Lama, the spiritual and political leader of the more than six million Tibetans and winner of the 1989 Nobel Peace Prize, of fomenting anti-Chinese uprisings in Tibet, which Chinese troops entered in large numbers in 1950.

Ngawang, a refugee brought up in southern India, had travelled to the United States for his Fulbright, a U.S. Information Agency-funded programme, on an Indian Identity Certificate, according to the campaign for Tibet.

The campaign said Ngawang "did raise money for his cultural project from private sources in the United States," but the government in exile, based in Dharamsala, India, denied that he had been sent to spy in Tibet.

"Many Tibetans have been arrested and tortured by the authorities in Tibet on the pretext that they have been sent by Dharamsala," Tempa Tsering, a government spokesman, said in a statement relayed by the campaign.

Until its letter to members of Congress, China had made no mention of the fate of Ngawang, despite appeals from Amnesty International, Human Rights Watch and a wide range of others.

Sanders and Senator Patrick Leahy, a Vermont Democrat, asked Ambassador Li in a letter on Tuesday to name the Americans alleged to have conspired with Ngawang.

"Along with other Americans of goodwill, we want very much to pursue close, friendly and productive relations between our peoples and governments, but cases like that of Mr Choephel continue to be a source of widespread concern," they wrote.