London ? Bird flu can be expected to spread to other countries, but the biggest threat of it mutating into a human virus that could kill millions remains in Asia, the World Health Organization said Monday.

The U.N.’s flu czar, meanwhile, called for resources to be focused on the continent that has seen its flocks devastated by the virus and 60 people killed since 2003.

Local authorities moved quickly to stamp out the disease where it was found in Romania and Turkey in recent days, but in Asia the virus has become widespread and the continued mixing of people and domestic fowl creates conditions more favorable for its mutation into a strain that could catastrophically affect humans.

“There’s no question that we will expect further outbreaks of avian disease in different countries,” said Dr. Michael Ryan, director of the Department of Epidemic and Pandemic Alert and Response at the WHO. “The Americas, Africa and the Middle East are also very much in our minds.”

The comments came as Greece reported preliminary tests found bird flu in a turkey and had narrowed down the virus to the H5 type. However, further tests are needed to confirm the finding and determine whether the virus is the deadly H5N1 strain from Asia that experts are tracking.

Health experts are trying to eliminate poultry outbreaks of the H5N1 bird flu strain for fear it could mutate into a human virus capable of killing millions of people. The more virus there is, the more opportunities there are for it to mutate.