WASHINGTON, Aug 20 (AFP) - An influential US congressman who slipped into Tibet disguised as a tourist warned Wednesday that the region is being "swallowed" by China through mass arrests and brutal repression.

"The clock is ticking for Tibet. If nothing is done, a country, its people, religion and culture will continue to grow fainter and could one day disappear," said Republican Representative Frank Wolf.

Wolf described his visits to prisons and monastaries in Lhasa and the countryside last week as a "nightmare tour" and said the Tibetans were eager to tell him about the horrible conditions of the region.

A relative of an imprisoned monk told Wolf that prisoners of conscience are routinely tortured, starved and isolated and that Tibetans are forbidden even to carry pictures of their exiled spiritual leader, the Dalai Lama.

Wolf, who said he dressed in "traditional tourist" garb and told no one of his identity, also noted that there are more Chinese in the capital Lhasa than Tibetans.

"China is swallowing Tibet. Stores, hotels, bazaars, businesses and tradesmen are largely Chinese," he said.

As the second ranking member on the Foreign Operations Committee, Wolf has been influential on many foreign policy issues and led the unsuccessful drive this year to deny China most favored nation trade status on human rights grounds.

Chinese troops took control of Tibet in 1951 and the Dalai Lama fled into exile eight years later after an abortive anti-Chinese uprising.

Wolf demanded that President Bill Clinton appoint a special, high-ranking envoy to pressure China on freedom of relgion and human rights in Tibet.

Clinton should also raise the subject when Chinese President Jiang Zemin visits Washington this fall and demand better access for Western journalists and lawmakers, he said.

Wolf said only three other US congressmen have visited Tibet since 1959 and that those official visits were too tightly controlled to allow any real scrutiny.

"The true story of Tibet is not being told," said Wolf. "America and the rest of the world must do more to urge China to back off from its clear goal to plunder Tibet."

Secretary of State Madeleine Albright announced last month that the administration would appoint a coordinator to promote a substantive dialogue between the Chinese government and the Dalai Lama.

But she stressed that while the coordinator would seek to meet with Tibetan leaders the contacts will not constitute any form of diplomatic recognition of a Tibetan government in exile or promote the independence or secession of Tibet from China.

Albright said that in view of this appointment she did not believe it necessary to have a high-ranking "special envoy" to Tibet such as Wolf has demanded.