The world must prepare itself to face an "inevitable" influenza pandemic, the World Health Organisation has warned.
Scientists are worried the bird flu epidemic could be echoed in humans
Scientists from the UN's health agency said the world is severely under-prepared, after they compared notes in Geneva.
Urgent action should be taken to boost health care, surveillance and the supply of key medicines, they said.
"We know another pandemic is inevitable. It is coming," said WHO Director-General Jong Wook Lee.
"And when this happens we also know that we are unlikely to have enough drugs, vaccines, health care workers and hospital capacity to cope in an ideal way," he added.
Scientists from 40 countries urged governments to create an international stockpile of essential but expensive and complex anti-viral drugs, and to increase the use of the annual influenza vaccine.
The fear gaining currency among health experts is that a human form of flu could spread as rapidly as the bird flu that has gripped Asia in recent months.
1918 Spanish flu killed 50m
1957 Asian flu killed around 1m
1968 Hong Kong flu killed 1m
There have been a number of cases of humans catching bird flu, and in some it has been fatal.
"The urgency has not changed, the avian influenza outbreak in Asia is not over," the WHO's senior flu expert, Klaus Stoehr, said.
Millions of people worldwide died in three influenza pandemics during the last century, and scientists say the threat of a repeat has grown in recent years.