President Jiang is said to be furious

But the decision to free the Tibetan also comes amid Western press reports that Chinese officials have discovered more than 20 spying devices in a Boeing 767 purchased from the US for use by President Jiang Zemin.

The American secretary of state, Colin Powell, says he does not expect President Bush's visit to be affected by the alleged bugging, while refusing to confirm or deny the reports - carried in Britain's Financial Times and the Washington Post.

Both newspapers reported that President Jiang was said to be furious.

One of six

Ngawang Choephel was born in Tibet in 1966 - though his family fled to India in 1968 - and afterwards went to study music in the US in 1994.

When he did not return home from his trip to Tibet, his mother reported him missing. The Chinese authorities then announced he had received an 18-year jail term.

In 2000 the family was granted the right to visit, and Mr Choephel told his mother that he had been on a hunger strike in protest at not receiving proper medical care.

He said he had liver, lung and stomach ailments, and possibly had a urinary tract infection and tuberculosis.

After that visit, Ms Sonam Dekyi said her son was very frail, just "skin and bones", with pale, almost yellow skin.