Turkish Prime Minister Tayyip Erdogan said none of the latest human victims were in a life-threatening condition and urged Turks not to panic.

Two teenagers died last week from bird flu in eastern Turkey -- the first reported deaths from the virus outside China and Southeast Asia. Their dead sister is also a suspected victim and hundreds of Turks have rushed to hospitals for bird flu tests.

Two teenagers died last week from bird flu in eastern Turkey -- the first reported deaths from the virus outside China and Southeast Asia. Their dead sister is also a suspected victim and hundreds of Turks have rushed to hospitals for bird flu tests.

"I have a sense that what is going on in Turkey can be brought under control relatively easily," said Guenael Rodier, head of a World Health Organization (WHO) team sent to investigate the outbreak.

Turkey has reported that at least a dozen people are infected with the virus, mostly children. Cases have been confirmed as far west as the central region around the capital Ankara sparking fears the disease could spread to people in mainland Europe.

The rash of cases in Turkey is the first time the virus has been detected in people outside east Asia since it reemerged in late 2003. It is now known to have killed at least 78 people, including two deaths in China newly documented by the WHO.

Rodier said it was not clear why so many people had been infected in Turkey so quickly.

"It is an open question if we are seeing a more efficient transmission from animals to humans," Rodier said.

There was also no answer yet to why the fatality rate was relatively low -- just two confirmed deaths so far -- against a rate in east Asia of roughly one death in every second case.

The WHO has said that victims appear to have contracted the disease from close contact with infected poultry, allaying fears it was spreading from person to person.

Experts fear the H5N1 strain of bird flu could mutate enough to allow it to pass easily among humans, sparking a pandemic in which millions of people could die.

DON'T PANIC

Turkey reported another human case of bird flu on Tuesday in the central province of Sivas.

However, Prime Minister Erdogan sought to dispel the sense of crisis that has overshadowed Turkish celebrations of the Muslim Eid al-Adha festival, a major national holiday.

"The situation is under control and we will continue to monitor it closely," Erdogan told a news conference.

"Unfortunately a mood of panic has emerged which gives an impression Turkey is under invasion," he added.

Snow and freezing temperatures in the east of the country are also hampering efforts to tackle the virus and may be allowing it to survive for longer.

Four people were taken to hospital with suspected bird flu near the Aegean coast -- one of Turkey's most important tourism centers -- adding to concerns the outbreak will harm country's important tourist trade.

Authorities in neighboring countries sprayed cars crossing from Turkey with disinfectant and checked luggage as they tried to stem the spread of bird flu.

POULTRY HIDDEN

Authorities said more than half of people undergoing tests for bird flu in Istanbul had tested negative.

Parts of suburbs of the capital Ankara and the business hub Istanbul have been sealed off for the culling of poultry. Inhabitants leaving the areas have been disinfected.

The number of provinces where birds have the virus has risen to 19. They include the western provinces of Istanbul and Bursa as well as Ankara, areas near the Black Sea in the north and areas in the east extending to borders with Iran and Armenia.

Since December 26 more than 300,000 poultry have been culled.

The authorities have sent teams of veterinarians in protective white body suits to a number of regions to cull poultry, seen as the best method of checking the disease.

The mayor of the eastern village of Dogubayazit, home to the children who died, said many people were hiding their poultry because they did not believe government promises that they would be fully compensated.