London: The head of the World Health Organisation on April 27 urged countries worldwide to co-operate in stemming the spread of Severe Acute Respiratory Syndrome (SARS), saying it was not too late to halt "the first epidemic of this century".

Gro Harlem Brundtland also dismissed criticisms that the United Nations body had overreacted in warning against travel to destinations including Hong Kong, parts of China and Toronto.

"We still have a window of opportunity (to stop the disease)," she told BBC television from Geneva of the spread of Severe Acute Respiratory Syndrome (SARS).

"At the moment we still have a chance to contain it, and to have it go down in places where outbreaks are happening and avoid its spreading to new countries," she said.

"This is still a challenge, that we can be able to... avoid this becoming a virus that is endemic around the world such as has happened with flu and HIV," she said.