The surge of SARS (search) cases in Beijing appears to have leveled off, but restrictions have been imposed on university students leaving the Chinese capital to stem the spread of the virus, officials said Friday.

Also Friday, the government banned foreign tourists from Tibet and other western regions until the end of May.

The announcements follow SARS-related restrictions that kept millions of Chinese home for the May Day holiday that began Thursday. Authorities cut the weeklong vacation to five days and have banned tourist travel.

Communist Party and health officials, speaking at a news conference shown live on Beijing (search) television, tried to reassure a frightened public, denying rumors the city is to be sealed off. They insisted that food and other supplies would be plentiful.

Their comments came as President Hu Jintao (search) called for the public to join in a "people's war" against severe acute respiratory syndrome.

A party official appealed to Beijing residents not to leave the city.

"We are trying to convince the local citizens to cut the amount of their outbound travel," Cai Fuchao, a member the city's party committee, said at a news conference.

At least 91 people have died in Beijing and more than 1,600 people are infected with the flu-like virus. Increases of more than 100 cases are reported almost daily. Throughout China, at least 181 have died and 3,799 have fallen ill.

High case numbers in Beijing "will continue for some time," Liang Wannian, deputy director-general the municipal health bureau, said at the news conference. But he said the situation "is stable and the upward trend has been effectively checked."

Judging by the experience of Hong Kong and the hard-hit southern province of Guangdong, Liang said Beijing's case numbers might start to decline in the next 10 days or so.

The restrictions on students require health checks for any who want to leave Beijing, Cai said. He said they are barred from rural and SARS-affected areas and would be quarantined when they return.

Cai said the rules were adopted to protect both the students and outlying provinces.

Though no SARS cases are reported in rural areas, health officials warn of potential disaster if the disease spreads to areas with poor health care in the countryside or China's poor west.

The State Tourism Administration banned travel to Tibet, which has no reported cases of SARS, on April 25, official Xinhua News Agency said. The report did not say when travel to other parts of China's west was banned.

Groups already in China were told to drop plans to go to those areas, Xinhua said. It did not say whether foreigners in Tibet would have to leave immediately.

Cai acknowledged that some students had fled the capital, but said there were only 39 SARS cases among Beijing's 670,000 university students.

Beijing has shut down its public schools, sending home 1.7 million students, told entertainment sites to close and built a 1,000-bed SARS isolation hospital.

A new SARS hospital north of Beijing has received its first 160 patients, said a spokesman for the city's Foreign Affairs Office who would give only his surname, Liu.

Thousands of people left Beijing last week and shoppers stripped grocery stores of food for fear quarantine measures might block new shipments.

"I would like to reiterate that no measures to seal off the city have been taken," Cai said. "With regard to whether the market supply in Beijing will be guaranteed, please rest assured there is no problem in this field."

Construction sites with housing for migrant workers from outside Beijing are to be sealed off to protect the laborers, Cai said. He said they would be checked twice daily for fever -- a key SARS symptom.

Meanwhile, Hu called for a "people's war" while inspecting anti-SARS efforts Thursday in the eastern port city of Tianjin, Xinhua said. The phrase echoes the strategy declared by communist founder Mao Zedong before the 1949 revolution.

"The masses should be mobilized ... to wage a people's war against the epidemic," the agency quoted Hu as saying.