There were moments today when this city of 13 million people appeared deserted.

At Bank of China branches, there were no lines. The traffic at Western Station, the city's main rail terminal, has dropped 75 percent, to 80,000 passengers a day.

Few tourists showed up at Silk Alley, the usually packed warren of vendor stands and shops that runs from Xiu Shui Street south past the U.S. Embassy. The deals were unprecedented.

Suddenly, China's capital is confronting the reality of the SARS virus.

"Now we're panicking," said Nancy Xue, a college student majoring in economics. She said most of her classmates ignored SARS until Monday, when professors called them into a meeting and distributed pamphlets about the disease.

"No one is going out," she said. "We're all staying in the dormitory. But we're worried the disease is going to find us here. It's scary."

A week ago, city officials said they were controlling the spread of the new and mysterious lung ailment, severe acute respiratory syndrome. China's state-run media cranked out reports guaranteeing that it was safe to travel during the May holiday season. But in the past two days, under the weight of international condemnation for not dealing seriously with the disease, authorities have changed focus.

The State Council, China's cabinet, is now devoting "100 percent" of its time to the epidemic, a government source said. One department of the Finance Ministry was closed after an official there came down with the virus, another source said. The closure has caused backlogs in money transfers from the central government to the provinces.

The government remains defensive about the disease. On Wednesday, the World Health Organization said health officials were not doing enough to combat infection, especially in Beijing.

Today, a government spokesman said officials have taken SARS seriously.

"The Chinese government still has all along handled relevant problems with a scientific attitude, a responsible attitude, including understanding the outbreak, evaluating the outbreak and reporting," said a Foreign Ministry spokesman, Liu Jianchao.

In meetings across the city, state-owned work units, colleges and government bureaus have told people to avoid gathering in groups and taking unnecessary trips. The number of people wearing face masks has increased noticeably. "The SARS epidemic is extremely serious," said one source who has attended government meetings on the issue.

Thousands of workers have been dispatched to disinfect city buses, taxis, office buildings and schools. Residents have snapped up 480,000 bottles of an herbal drink, on word that it protects against the disease. Mei Qun, the general manager of Tongrentang Pharmacy, which concocted the brew, smiled when he discussed the sales but promised to "keep profits to a minimum."

Vice Premier Wu Yi, who is coordinating the government's response to the epidemic, has warned representatives of the service and travel industries about severe economic losses, sources said. The China International Travel Service has already reported a cancellation rate of 80 percent.

"SARS, for sure, will have an influence on the economy's performance in China," said Yao Jingyuan, an economist at the National Bureau of Statistics. Yao said it was "too early to make any forecasts," but private economists said China's economic growth rate this year would be at least 1 percentage point lower than previously estimated.

SARS is believed to have originated in November in the southern province of Guangdong. The virus has spread to 26 countries, infecting more than 3,400 people and killing at least 165, according to the WHO. China has experienced at least 1,457 cases of SARS, with at least 65 fatalities.

Chinese doctors said Guangdong officials responded slowly to the disease and neglected to advise Beijing and neighboring Hong Kong to take precautions against contamination. As a result, about 80 percent of the reported SARS cases have been in China and Hong Kong. The WHO today reported 1,297 infections in Hong Kong and 65 fatalities.

At the SARS ward of Ditan Hospital in Beijing today, health care workers provided journalists with anti-contamination suits before taking them on a tour. "See what we have to do every day?" said one nurse, who told reporters that she knew "many, many" health care workers who have been infected with the disease all around Beijing. "We're petrified. We're so afraid we can hardly work."

Inside the ward, 25 patients lying in beds could be seen through small windows. All appeared to be breathing on their own, an indication that their cases were not serious. While officials say that 80 percent of patients recover from SARS, 20 percent develop serious complications and are placed on respirators.

Among recent fatalities from the disease were a reporter from China Central Television who went to the hospital with a broken leg and an employee of the New China Film Co. who had appendicitis.

Two departments at Beijing University canceled classes, as did several departments at the Central University for Nationalities, when instructors or students were infected with the disease. A kindergarten class was sent home after the relative of a student was infected. The elementary school attached to Beijing Foreign Languages University was also closed because of concern about SARS.

Nancy Xue, the economics student, is from Ningxia, a poor province in western China that reported its first case of SARS today. Doctors said there actually were eight cases in the province. The WHO has expressed concern that China's health care system will not be able to handle SARS after it moves into the country's interior, which lacks the personnel and money to fight the disease.

"My parents have no idea what SARS is," Xue said. "They want me to come home, but I worry about catching it on the train."

A city worker in Guangzhou disinfects a train window. Doctors say officials in the southern city failed to warn the rest of the country about SARS.