The World Health Organization (WHO) has confirmed Turkish health officials tests that show a fourth person, a young girl, has died from the H5N1 virus.
Indonesia also suspects that a 13-year-old girl has died of bird flu; two of the girl's siblings are also sick, but the WHO has yet to confirm this.
To date Indonesia has reported 12 deaths from bird flu.
The brother of the Turkish girl is in a critical condition, and has also tested positive for the H5N1 virus.
Meanwhile authorities in Turkey continue the slaughter of thousands of birds in an attempt to contain the outbreak.
Turkish authorities have culled 932,000 birds over the past two weeks to try to contain the crisis.
The Agriculture Ministry had imposed a nationwide ban on the transit of poultry.
According to the WHO the young girl who died came from the same eastern town of Dogubayazit, where three other children died from the virus earlier this month.
All were apparently infected in late December or early January.
Until these deaths human victims of the virus had all been in Asia and it demonstrates quite clearly that the lethal H5N1 strain has reached the gateway to Europe, Asia and the Middle East.
Turkish authorities say they have had a total of 20 human cases, including the four deaths, in two weeks.
The virus has claimed at least 79 lives since 2003 and has infected some 150 others.
Nevertheless the U.N. Food and Agriculture Organization FAO maintains that Turkey can still prevent bird flu from becoming endemic among its bird population.
Juan Lubroth, senior FAO animal health officer, says there is still time to prevent the virus spreading if the Turkish veterinary services have access to enough resources.
Bird flu has been found in wild birds and poultry over a third of Turkey's territory, hitting villages from Istanbul at Europe's gates to Van near the Iranian and Iraqi borders.
The FAO has previously expressed fears that the virus could gain a foothold in neighboring countries such as Georgia, Iran, Syria and Armenia.
The virus is already endemic across parts of Asia and scientists have long feared the H5N1 strain could mutate from a disease that affects mainly birds to one that can pass easily between people, leading to a human pandemic.
At a donor conference this week the senior U.N. coordinator for avian and human influenza will push for money to be pledged to fight the spread of the virus.
The World Bank aims to raise $1.2 billion at the conference in Beijing, but David Nabarro said he would like to see the world investing $1.5 billion.
Guenael Rodier, head of the WHO mission in Turkey, says more human cases are to be expected before the virus in birds has completely disappeared, but he believes the tally it is going down daily.
Elsewhere, an Israeli hospital tested a Palestinian for the bird flu virus on Monday after his chickens died and he became sick.
Greece is urging its citizens to avoid unnecessary travel to Turkey, but as yet has not closed its borders.
Iran has also culled tens of thousands of birds and has closed its border with Turkey to day trippers and has banned the import of live birds and poultry products from Turkey.
While Turkish financial markets shrugged off the crisis as trading resumed after a long religious holiday, fears remain that the outbreak will significantly damage Turkey's $20 billion tourism industry.