Turkish officials say two teenagers are believed to have died from bird flu. If the cases are confirmed to be the deadly H5N1 strain, they would be the first human fatalities from the virus outside southeast Asia and China.

Turkish Health Minister Recep Akdag announced late Wednesday that a 14-year-old boy died from bird flu last week. Hours later, Turkish officials announced that the boy's sister had also died in a hospital in the southeastern city of Van, where the siblings were being treated.

Hospital officials say two more patients from the same family have been hospitalized and are undergoing treatment for bird flu.

A spokesman for the World Health Organization said Turkish authorities have only confirmed that the dead boy had the H5 form of the flu virus, and were awaiting results of further tests to establish whether it was the deadly H5N1 strain that has killed more than 70 people in Asia since 2003.

If the deaths are confirmed as being the result of H5N1, it would mark the first time the deadly virus has spread outside China and Southeast Asia.

WHO officials stress that the cases should not be viewed as a start of a pandemic, because bird flu has so far not been passed between humans.

Avni Sahin, the chief doctor at Van University Hospital, said nine patients were being treated for bird flu. Two of the patients were reported to be in critical condition. Emergency supplies of the anti-flu drug, Tamiflu, have been dispatched to Van.

Meanwhile, Turkish Agriculture Minister Mehdi Eker said that bird flu had been identified in the town of Dogubayazit, where the two teenagers who died reportedly were infected. The family of the dead brother and sister were reported to be poultry farmers.

Local officials say more than 1,000 chickens, geese, ducks, and turkeys have been slaughtered in the region.

Turkey is on the path of migratory birds from Siberia that are believed to be carrying bird flu. An outbreak was reported three months ago in western Turkey near a wild bird sanctuary, but was rapidly contained. Critics say authorities did not display the same efficiency in the town of Dogubayazit, which is desperately poor and populated mainly by ethnic Kurds.