The head of the World Health Organisation (WHO) urged countries worldwide to co-operate in stemming the spread of SARS, saying it was still not too late to halt "the first epidemic of this century".
Gro Harlem Brundtland also dismissed criticisms that the United Nations organisation had overreacted in warning against travel to destinations including Hong Kong, parts of China and Toronto in Canada.
"We still have a window of opportunity (to stop the disease)," she told BBC television from Geneva of the spread of SARS.
"This is still a challenge that we can be able to pursue to avoid this becoming a virus that is endemic around the world such as has happened with flu and HIV," she said.
"We must take precautionary measures now.
"It is now we have a chance to contain it and we must use public health tools to contain it," she said.
She added that if swift action was not taken "we will not have done the right thing with the first epidemic of this century".
The former Norwegian prime minister, who has headed the WHO since mid-1998, dismissed the suggestion that Toronto - where 19 people have died from SARS against more than 120 each in Hong Kong and China - had been singled out in the travel warning to avoid allegations of bias against Asia.
"That would be outrageous," she said.
The respiratory illness has killed at least 293 people and infected nearly 5000, most of them in Asia.