China stands accused of concealing the scale of the problem
China, Hong Kong and neighbouring Singapore have taken drastic action to contain the Sars virus, which has now claimed at least 204 lives worldwide.
The Chinese Communist Party has sacked the Health Minister, Zhang Wenkang, and Beijing Mayor Meng Xuenong from their posts in the party, amid accusations that officials had covered up the true scale of the epidemic.
The authorities also cancelled the traditional week-long May Day holiday because of fears that increased travel would spread the deadly pneumonia-like Severe Acute Respiratory Syndrome.
China's official death toll is now 79, with 1,807 confirmed cases of the illness.
There is no cure or vaccine for the virus,
and China's efforts are seen as vital to controlling the epidemic, which has hit business and travel in Asia. The death rate from Sars infections is put at about 4%.
In Singapore, the authorities have placed 2,400 workers in quarantine and closed a large vegetable market for 10 days after a man working there was diagnosed with Sars.
And in Hong Kong the death toll from Sars has risen to 88 - the highest total in the world. Seven deaths from Sars were reported there on Sunday, following 12 deaths on Saturday.
The Sars scare has left much of Hong Kong looking like a ghost town, as people try to avoid crowds.
The territory has launched a massive clean-up, mobilising thousands of volunteers - from housewives to government officials - to disinfect apartment blocks, shops and restaurants.
Sars has also claimed 14 lives in Canada. The authorities closed the country's largest trauma unit for at least 10 days after four new cases of suspected Sars were discovered among health staff.
On Sunday the Chinese health ministry said there were 346 confirmed cases and 402 suspected cases in Beijing alone, and that 18 people had died from Sars in the capital.
The number of cases in Beijing is nine times higher than the previous official figure of 44 cases and four deaths.
Threat to rural areas
The World Health Organization (WHO) has voiced concern that many poor and rural areas of China with only rudimentary healthcare face much less scrutiny.
The BBC's Holly Williams in Beijing says controlling the outbreak will be difficult after China's slow and secretive initial response.
Densely-populated Hong Kong has been hit hard
The virus has spread to 13 provinces and infected nearly 2,000 people, she says.
The political bloodletting in China is intended to show the international community the authorities are doing something about Sars, our correspondent says.
The cancellation of China's national "golden week", which was due to start on 1 May, means forfeiting a huge boost in consumer spending.
During the holiday, students usually return home, migrant workers go back to their villages and the new middle classes go on tourist trips.
"This year, we will not have the week-long holiday," vice health minister Gao Qiang told reporters, calling the move a "highly rigorous measure".
We have only identified the coronavirus in 50% of the people being treated for Sars
Canadian health ministry official
"This doesn't mean there will be no travelling and tourism going on," he said. "We are just against the massive movement of people."
The education ministry has printed prominent warnings in state media urging students to remain on campus.
People in China's poor provinces tend not to visit the doctor because it is too expensive or because there is no doctor. Health experts say the virus may therefore never be fully eradicated.
It is believed to have originated in China's southern Guangdong province in November.
Malaysia on Sunday also announced a second possible Sars death, that of a 30-year-old man.
The WHO has identified the coronavirus - a virus family which causes the common cold - as the cause of Sars.
But Canadian heath officials have cautioned that it may not be the only cause of the disease.