European Union experts were due to arrive in Romania to help confirm suspected cases there of the potentially deadly bird flu and arrange technical assistance.
The continent remained on alert against an outbreak of the new variant of the disease, which scientists fear could mutate into a global pandemic that could take the lives of millions of people.
An epidemiologist from the British laboratory working on identifying the flu strain identified here and an expert from the EU's technical assistance bureau were to arrive Monday to assess the risk.
Both Romania and Turkey, where suspected cases have also been discovered, scrambled to cull birds thought to have come into contact with the disease.
Hungary Monday joined Poland in banning poultry imports from Romania in growing economic disruption caused by the outbreak.
Authorities in the northwestern Turkish province of Balikesir slaughtered thousands of birds after avian flu was detected in the region.
Following an initial cull of 2,000 birds, a further 3,000 head of poultry were gassed in the Kizikza region overnight Sunday to Monday, according to the NTV news channel.
A senior health official in the region, Adnan Pac, said all birds in a three-kilometer (two mile) quarantine zone would be slaughtered and that the quarantine would be maintained for three weeks.
The flu was detected close to a nature reserve and lake that attracts migratory birds, feared to have brought the disease from Russia and central Asia.
In Romania, where bird flu was identified in three ducks, nearly 15,000 birds were scheduled to be slaughtered and incinerated around the village of Ceamurlia de Jos, which was cut off from circulation.
The virus strain detected in both countries has not been identified with certainty. That could take several more days, experts said.
The potentially killer strain is known as H5NI. It has infected 112 people in 10 southeast Asian nations, of whom 60 have died.
The cases were mostly infected directly by birds, and experts say the disease does not easily spread from person to person.
However, the fear is that the disease could be highly infectious if it mutated with ordinary kinds of influenza that could turn it into a global pandemic.
To reduce the risk of this happening, both Turkey and Romania were giving flu shots to populations at risk.
Romanian officials said up to 125,000 people in the Danube delta, where the first suspected cases have been identified, are due to be vaccinated. In addition, vaccination campaigns were being carried out in six regions.
"It is very important because if leads to a strengthening of general immunity," said a health ministry official, Oana Grigore.
Although the flu strain found in Romania had not been confirmed as being the H5N1 variety, "we have to act as though it were," said Agriculture Minister Gheorghe Flutur.
In Rome, Health Minister Franceso Storace said he was "concerned" about the spreading of bird flu toward Europe.
"There are reasons to be worried but not alarmed," he said. If a human form of the disease does develop, it would take three to six months to produce a vaccine, which he said would be sufficient "because in the case of a pandemic, it would explode in Asia and not arrive immediately in Europe."
