The dismissal of Mayor Meng Xuenong came shortly after he and China's health minister were removed from key Communist Party posts, and the Health Ministry announced that the number of cases of severe acute respiratory syndrome in Beijing had jumped from 37 to 339.
Detailed accounts in state-run newspapers said senior party officials accused Meng of failing to gather information on SARS, track new infections and trace people who might have been exposed to the mysterious ailment.
A Beijing government spokesman would not confirm the firing of the mayor, who was appointed three months ago.
The flu-like SARS has sickened more than 3,800 people and killed at least 217 others around the world as of Monday, according to the World Health Organization. The illness has killed some 94 people and infected more than 1,400 in Hong Kong, while mainland China has reported 86 deaths and more than 1,900 people infected nationwide. Singapore and Canada have also been hard hit by the virus.
China called off its weeklong May Day vacation in hopes of stopping tens of millions of people from traveling and spreading the virus.
Cases of the SARS have now appeared in various parts of China, including the northern region of Inner Mongolia, the eastern province of Zhejiang, and Guangdong and Guangxi in the south.
"I think it will be quite a challenge to contain SARS within China, especially those provinces which have very limited resources," Henk Bekedam, the WHO representative in China, told Reuters.
China's dismissal of the Beijing mayor and its new sense of urgency about SARS comes after weeks of criticism at home and abroad of its slow response to pleas for information and cooperation in fighting the disease.
Meng was replaced "in order to improve the Beijing region's handling of SARS prevention work and ensure overall stability in the capital," the newspaper Beijing Youth Daily quoted He Guoqiang, chief of the party organization department, as saying. Meng was dismissed Sunday as deputy party chief for Beijing -- a more important post than mayor.
On Friday, China's Communist Party leadership declared an all-out war on SARS and ordered officials to fully disclose the extent of the disease's spread.
Other countries are continuing attempts to stop the spread of the disease.
Singapore announced that all 2,400 employees of a vegetable market are under quarantine after a coworker fell ill.
Hong Kong's increased efforts to find people with the disease has led to the identification of 150 suspected SARS cases. Hong Kong Chief Executive Tung Chee-hwa said efforts to contain the spread of SARS by quarantining households of victims and tracking down potential contacts were paying off.
Canada reported its 14th death from SARS, as a major Toronto hospital closed several units after staff members began to show symptoms.
Sunnybrook Hospital in Toronto, which has Canada's largest trauma unit, closed its critical care, cardiovascular intensive care and SARS units Saturday. Officials believe staff members were exposed to the virus a week ago while treating a patient.
The closing will place a "huge burden" on Toronto's health care system, said the hospital's president and chief executive, Leo Steven.