The government has banned most hotels in Beijing from accommodating members of the Uighur ethnic group from northwestern China, telling some proprietors that security services fear demonstrations during the upcoming 16th Communist Party Congress.

Proprietors at several hotels, contacted by telephone, said police told them not to allow Uighurs to stay in their establishments and to report any Uighurs who appear at their counters. One proprietor said he was told by police that 700 Uighurs are believed to have infiltrated Beijing and plan to hold demonstrations against China's rule of Xinjiang, their home region.

Beijing's ban on Uighurs spending the night is just one of a series of measures security forces in the capital have taken in advance of the party congress, which generally occurs every five years and anoints a new leadership of the 66 million-member Communist Party. The congress will open Friday and last for about one week.

On Monday, Chinese police detained a government official turned democracy activist, Fang Jue, and tightened surveillance of another dissident, Chen Zhiming. Both have recently been released from jail sentences imposed on them for advocating political reforms. The party also announced it had stripped a former top banker, Wang Xuebing, of alternate membership in the Central Committee and expelled him from the party.

"Wang Xuebing took advantage of his position to embezzle, and accepted bribes," said the official New China News Agency. "He had a debauched lifestyle and corrupted morality."

Police have established checkpoints on major arteries leading into the capital and on highways that ring the city. Drivers of vehicles with out-of-town license plates must produce a permit to enter the city. Squads of police raided nightclubs and did random urine checks at Beijing bars checking for drug use, especially of ecstasy.

Police are also checking the identification papers of people entering Tiananmen Square, the political heart of China. One police official at the square said authorities there were concerned that members of the banned spiritual movement Falun Gong could seek to use the congress to protest the two-year crackdown on their group.

Since the Sept. 11, 2001, attacks on the United States, China has sought to equate its struggle against small groups of Uighur separatists with the U.S. fight against terrorism. China's struggle got a major boost recently when Washington backed a bid to have an organization of Uighur separatists placed on the U.N. terrorist watch list.

A Turkic ethnic group, China's 8 million Uighurs live mainly in Xinjiang, in the far northwest. Many Uighurs complain that China has discriminated against them and their Islamic culture since Communists took control of the region after the revolution in 1949.

An employee at the reservations desk of the Capital Hotel said the hotel was informed by police that it had to "strictly control Uighurs and strictly check them." "You know," the employee said, "those Xinjiang groups have connections with Afghanistan."

Across town, at the Jimen Hotel, an employee said the local precinct banned Uighurs from staying at the hotel. "In the beginning, when Uighurs stayed here we had to report it," the employee said. "Now they can't stay here at all."