Officials in Taiwan also talked tough, announcing that mandatory home quarantines for suspected SARS patients in Taipei would be extended from from 10 to 14 days. Mayor Ma Ying-jeou said a special SARS taskforce would enforce the quarantine rule and those who broke it would be detained.
Doctors in Hong Kong say they have helped some seriously ill SARS patients survive by administering a serum that contains antibodies to the virus from patients who recovered.
Severe acute respiratory syndrome has killed at least 464 people and infected more than 6,500 worldwide - including 206 deaths and 4,280 cases in China alone.
To ease the burden of health workers overwhelmed by rising SARS cases in Beijing, China's military is sending 1,200 doctors and nurses to the Chinese capital.
The city government is also eleven hospitals to the six already designated to handle SARS, and on Tuesday began using ambulances to move hundreds of non-SARS cases to other institutions.
The Philippines reported seven more SARS cases Tuesday, raising to 10 the total number of people known to have been infected there.
In the United States, the University of California at Berkeley said it will turn away new students from SARS-hit China, Taiwan, Singapore and Hong Kong in coming months. In what is believed to be the first such move by a major U.S. educational institution, about 500 would-be students will get their fees refunded.
In Brussels, European health ministers met in an emergency session to standardize anti-SARS measures across the continent, which has reported 33 probable cases in France, Britain, Germany, Italy, Ireland, Sweden, Poland and Spain. None have died.
Media reports in Beijing quoted Chinese Premier Wen Jiabao as saying that while progress against SARS had been made, the outbreak in the Chinese capital "still remains grave."
Wen ordered officials at all levels to work hard against the illness, the official Xinhua News Agency reported. He also warned that lax individuals will be punished harshly.
"It is very important to do the job well in Beijing, which is the capital and the political and cultural center of the country," Wen was quoted as saying.
Meanwhile, at least 16,436 people were quarantined in apartments, university dormitories, hospitals and construction sites around Beijing, city officials said. More than 5,600 had been released.
Beijing has more than 1,890 cases of infection - nearly half the county's total - and 103 deaths.
To stop the spread of SARS, Beijing has closed schools, built a new 1,000-bed hospital on its outskirts and ordered travel restrictions.
In Hong Kong, hospitals have typically prescribed a combination of the antiviral drug ribavirin and steroids for SARS, but some patients who didn't respond to that regimen have gotten serum made up from patients who developed antibodies and recovered.
"This treatment has only been applied to those critically ill patients when everything else fails," said Janet Chow, a spokeswoman for the medical faculty at the Chinese University of Hong Kong. "It is used as an alternative treatment."
Hong Kong has reported 1,637 cases of SARS, and 187 deaths.
Government-owned radio RTHK said about 50 patients have been treated with the serum and the results have been good, with patients generally recovering and leaving the hospital more quickly, with a lower mortality rate.
In Colombia, a 20-year-old woman who spent nine months in Hong Kong may have the first case of SARS in Latin America, health officials said. Juan Lopez, Colombia's deputy social welfare minister said she was hospitalized last month and fully recovered.
Tests are being carried out to confirm whether she had the illness.
In Geneva, a global air industry group said new airport screening methods have kept SARS-infected passengers from boarding airplanes and reduced the risk of disease transmission to other passengers.
"Travel by air is safe, even in this situation," said Giovanni Bisignani, director general of the International Air Transport Association. "No case has been developed on an airplane since prescreening" began in early April, he said.
Before that there were fewer than five possible cases of transmission of the disease on board a commercial airliner, "and we had flown in that period of time over 200 million passengers," Bisignani said.
Airlines, particularly those flying in Asian skies, have reported a dramatic drop in business.
In the Netherlands, KLM Royal Dutch Airlines said its passenger traffic in April slipped 7 percent on the year, hurt by the war in Iraq, and is still declining because of SARS.
On its key Asian Pacific routes, which make up 20 percent of overall sales, traffic dropped 24 percent from a year earlier.
"SARS is the big uncertainty now, making it hard to look forward," said SNS Securities analyst Geert-Jan Hoppers.