Bird flu is suspected in the deaths of three people in Indonesia, the country's health minister has said.
Bird flu resurfaced in Asia at the beginning of 2004
If confirmed, the victims - a man and his two young daughters - would be Indonesia's first human fatalities from the disease.
Millions of birds have died or been culled across Asia in the last few years, in an effort to stem bird flu.
Since January 2004 at least 53 people are known to have died of the virus - in Cambodia, Vietnam or Thailand.
Indonesia has reported cases of bird flu in poultry in several provinces this year and recently confirmed that a farm worker had tested positive for the virus.
But until now there had been no reports of suspected human fatalities.
Health Minister Siti Fadillah Supari said on Friday that the three victims - a 38-year-old man and his two young daughters - had lived in Tangerang on the outskirts of Jakarta.
She said the first victim - a one-year-old infant - died several days ago and had already been buried, and that tests on the other girl and the father had proved inconsistent.
H5N1 BIRD FLU VIRUS
Principally an avian disease, first seen in humans in Hong Kong, 1997
Almost all human cases thought to be contracted from birds
Isolated cases of human-to-human transmission in Hong Kong and Vietnam, but none confirmed
"We have sent specimens to Hong Kong to confirm the results, which will take seven to 10 days," she said.
More than 300 people who have been in close contact with the family are being placed under surveillance.
Ms Supari said she was concerned the three victims could have contracted the disease via human-to-human transmission, because they had no known contact with poultry.
But World Health Organization representative Georg Petersen said that in his experience, a more thorough investigation could turn up evidence to the contrary.
"In other countries, this is often the case," he told the Associated Press. So far humans have only contracted bird flu after coming into contact with infected animals.
But the real fear is that the virus might develop into a form which can be transmitted from person to person, raising the possibility of a global pandemic.