The World Health Organisation (WHO) urged global cooperation, as the bird flu death toll reached 78 people worldwide, including the two Turks who perished last week.
They were the first human casualties outside East Asia.
Bird Flu has infected 13 other people in Turkey and spread from the country's remote east to its western shores, with officials culling hundreds of thousands of winged animals.
But the UN Food and Agriculture Organization (FAO) said the virus may be spreading despite Ankara's attempts to curb it.
"The highly pathogenic avian influenza virus H5N1 could become endemic in Turkey and poses a serious risk to neighbouring countries," FAO senior animal health officer Juan Lubroth said.
"Far more human and animal exposure to the virus will occur if strict containment does not isolate all known and unknown locations where the bird flu virus is currently present," he added.
Two more deaths in China
In China, two more people died from the disease last month, a 10-year-old girl in the southern province of Guangxi and a 35-year-old man in the eastern Jiangxi province, according to the WHO.
Five people have now died out of eight infected in China and there are grave fears for a six-year-old boy in the central province of Hunan.
The latest events in China, which has the world's biggest poultry industry, triggered further alarm bells just a day after the government warned the H5N1 crisis had not yet peaked and human-to-human transmission remained possible.
The WHO's spokesman in Beijing, Roy Wadia, said the two were being cared for in hospitals.
"Both were in critical condition, so it is not surprising that they have passed away," Mr Wadia said, adding the China's Health Ministry had informed his organisation of the fatalities.
"This disease is entrenched in the environment and it is going to be a very big challenge," he added.
"It is a big concern in a huge country like China that has a lot of backyard farms and a lot of areas where surveillance is not that good."
Nevertheless, Mr Wadia praised China for its efforts and its attitude in fighting the virus.
"The government has certainly not at all been complacent about this. They are remaining quite realistic," he said.
In particular the Chinese government has warned against the nightmare scenario of bird flu starting to spread from human to human, rather than the current transmission pattern from bird to human.
The statement came only hours after the announcement of a new outbreak among farm birds in the southern province of Guizhou, the 33rd outbreak in China since early 2005.
More than 40,000 poultry have been culled and another 16,000 poultry have died from the disease in the provincial city of Guiyang.
The vast majority of China's bird flu cases have taken place within the past three months.
Aside from its enormous poultry population of 14 billion birds and backyard farming practices, China is considered particularly exposed to the virus because three of the world's eight main migratory routes for birds cut across the country.
Frontline preparations
The FAO also warned neighbouring Armenia, Azerbaijan, Georgia, Iraq, Iran and Syria that they were in the frontline in case of a spill from Turkey.
Faced with the threat of contamination of a virus that knows no boundaries, Georgia said it was disinfecting all of its border posts.
Authorities in the Kurdish-held north of Iraq banned local trading in live chickens and ordered all vehicles coming in from Turkey to have their tyres sprayed with disinfectant.
The warning also led several European states -- especially those lying on the route of migratory birds, who are blamed for the spread of the virus, to introduce heightened measures.
French Health Minister Xavier Bertrand has presented an updated plan to tackle, including massive stockpiles of antiviral drugs, like Tamiflu and Relenza, and face masks.
Reserves of the drugs which currently stand at around 14 million courses day, will rise to 33 million in 2007 for a population of 60 million, he told lawmakers.
And by the end of 2006, a billion facemasks will be available for distribution to the general public, to discourage the spread of virus-laden droplets by coughing and sneezing.
Two hundred million professional-quality facemasks will also being stockpiled for use by health workers likely to be in close proximity to flu-infected patients.
Romania joined Britain and Russia in advising its citizens to stay away from Turkey, but the WHO”s Regional Director for Europe, Dr Marc Danzon says, "There is no danger (in coming) to Turkey."
The EU's executive arm, the European Commission, will also extend its monitoring of wild birds and poultry until the end of the year and said it would contribute up to two million euros in funding for laboratory testing.
In Germany, Environment Minister Horst Seehofer said it was "highly likely" that the government would issue a new order to keep poultry shut indoors in an attempt to prevent it coming into contact with infected birds.
Italian Health Minister Francesco Storace said his country was setting up a crisis unit which would go into action in the event of an epidemic breaking out.
Portugal meanwhile said it was among the best prepared countries on the continent, having ordered 2.5 million doses of medication to treat bird flu, enough for a quarter of the country's population.
And Switzerland said it was introducing heightened measures at airports to prevent wild birds and poultry from Turkey being brought into the country.
Denmark and Norway announced similar measures, while Sweden advised people visiting Turkey to stay away from markets and poultry farms.
Bulgaria, sandwiched between Romania and Turkey, is on high alert to prevent an outbreak of bird flu, but no cases of the disease have been detected so far.
And Estonia's veterinary service has begun inspecting the Baltic state's poultry farms for bird flu.
"All poultry farms, irrespective of size, will be checked in January and February to make sure they are not infected with bird flu," the Estonian Veterinary Service said in a statement.
The Czech Republic has also stockpiled enough doses of Tamiflu for 1.7 million people, while Croatia said it was increasing checks on people who had visited Turkey.
Tokyo conference
Officials from 21 countries and organisations are looking for ways to prevent bird flu from spreading around the world as a two day conference opened in Tokyo.
The meeting, hosted by the WHO will discuss early response measures if and when a potential human pandemic strain emerges, and how to stockpile antiviral medicine and other supplies.
"We must try to ensure that we will be ready to respond instantly with all the weapons at our disposal should the early signs of influenza pandemic appear," said Shigeru Omi, WHO director of the Western Pacific Regional Office.
"By the time we leave here, we must all have a clear understanding of what has to be done to enable us to contain a virus with pandemic potential," he said in an opening speech.
No pandemic, yet
The WHO said there was no evidence, however, that the virus has mutated into a form able to jump from human to human -- the feared scenario that could trigger a pandemic capable of killing millions of people.
Experts say the people infected in Turkey contracted the virus after coming into contact with infected animals.
"There is no transmission (from) human being to human being in a mutation that would (create) the danger of a pandemic. We are looking, but that is not the case," Dr Danzon said.
"There is no need to panic," he added.
On Tuesday, Turkish officials confirmed a 15th case of human infection of the deadly H5N1 virus, bringing to 13 the number of people now under treatment.
Two infected children, from the same family in Dogubeyazit, died from the deadly virus.
"They (the patients) are under control. Two of them have difficulties, but these will be overcome," Turkish Prime Minister Recep Tayyip Erdogan said.
Scores of people have also been taken to hospital amid fears they may also have contracted the virus.
The absence of a centralised information system, is creating confusion over the exact number of Turkish provinces where the Bird Flu has been reported.
Revising an earlier statement, the Agriculture Ministry said there were confirmed cases in 11 of Turkey's 81 provinces and said 13 other provinces were suspected to have outbreaks.
But statements by provincial governors contradict this figure.
An AFP count Wednesday put the number at 23; other media tallies go as high as 27.
Turkey’s Poultry business threat
The bird flu outbreak, in Turkey, has led to a huge cut in poultry consumption and is threatening the very survival of a sector that provides tens of thousands of jobs, according to an industry specialist.
"Poultry consumption plummeted by nearly 70 percent," said Yuce Canoler, general secretary of BESD-BIR, the White Meat Industry Union that represents Turkey's major poultry producers.
"The sector has been hit in the heart," he said.
The days that followed the Bird Flu deaths of two teenage siblings saw poultry consumption drop to 10 percent, its lowest level yet in Turkey, Canoler said.
More than 306,000 fowl, belonging mostly to small producers, have been culled so far, according to government figures.
A first outbreak of the disease occurred in a turkey farm in the northwestern province of Balikesir in October and led to a first drop in consumption, despite being quickly contained and with no human contamination.
"This second wave could kill our sector off," Canoler said.
Turkey's industrialized northwest is home to huge industrial chicken farms.
Chickens represent 98 percent of the industry output, with only marginal farming of turkeys, geese and ducks.
Turks consumed 13.5 kilos of white meat per person in 2005, according to BESD-BIR, but the figure should plummet this year, Canoler said.
The sector’s annual turnover of nearly two and a half billion euros could be at risk.
The sector's estimated losses since the first outbreak, despite government subventions, is already around 100 million euros.
Talks are under way between producers and the government to find ways of limiting the damage, including possible low interest loans and grants, a source at the agriculture ministry in Ankara said.