Health officials in Turkey say a girl who has has died in the eastern region of Turkey is suspected to have had bird flu.
They are waiting further confirmation that the teenage girl, from the same area where the virus has already killed three siblings, had the deadly virus.
If this is the case, her death will bring the number of deaths in Turkey this month to four.
Huseyin Avni Sahin, chief doctor at Van University hospital, is expected to make a full statement regarding her death.
The H5N1 virus has been found in wild birds and poultry across large parts of Turkey, particularly in poor villages stretching from Istanbul to Van near the Iranian and Iraqi borders.
The girl's brother is apparently also in Van hospital suffering from bird flu-like symptoms and is in a critical condition.
The children were reportedly taken to Van hospital after being in contact with sick chickens.
They were treated with the antiviral Tamiflu.
According to the World Health Organisation (WHO), the victims have all contracted the disease from close contact with infected poultry; some of the children are said to have been playing with birds or helping kill them for food or sale.
The deaths in Turkey are the first human cases reported outside east Asia since H5N1 re-emerged in 2003.
Although the virus remains essentially a bird disease, it has infected as many as 150 people and killed at least 78.
WHO doctors say there is no evidence of human-to-human transmission in the Turkish cases.
The WHO also says that of the dozen bird flu patients still in hospital most are not in a critical condition but are still receiving treatment.
Three people have recovered and were released from hospital last week.
It is reported that two more children, aged 11 and 13, have been hospitalised in Istanbul with bird flu-like symptoms after coming into contact with chickens in the town of Gebze.
It is unclear whether the children have been tested for bird flu.
Bird flu has only been confirmed in poultry in Istanbul, a busy city of 12 million people close to Europe.
The disease has swept across a third of the country since the start of the year and 600,000 wild birds and poultry have been culled in an attempt to contain the virus.
An information campaign has also been launched to urge people to avoid contact with birds and stop their children playing with domestic poultry.
Health officials are visiting houses particularly in the east of Turkey, searching for sick birds.
The Food and Agriculture Organisation (FAO), are concerned that the virus risks becoming a constant problem in Turkey as it is in poultry in parts of Asia.
Turkey's $US3 billion poultry industry is on the brink of collapse and the government has set up a committee to discuss the crisis.
Proposals to deal with the situation are expected shortly.
A team of animal and human health experts from the U.S. will join experts already in Turkey from the WHO, the U.S. Centers for Disease Control and Prevention and the FAO, to assess the avian flu situation there.