Greece has become the latest country to report a case of bird flu as the virus appears to spread across Europe.
Romanian authorities are taking no risks with the potentially lethal virus
The country's agriculture ministry said a form of the virus had been found in a turkey on a farm on the Aegean Sea island of Oinouses.
Twelve swans have also tested positive for bird flu in a second cluster in Romania.
And the European Commission has ordered urgent tests on dead birds found in Croatia.
At this stage, neither of the new outbreaks in Greece or Romania have been confirmed as the lethal H5N1 form of the bird flu virus, which has been linked to more than 60 human deaths in Asia.
However, tests are continuing, and the Greek outbreak is known to involve the H5 strain, of which the deadly form is a member.
Meanwhile in Asia, the deadly H5N1 strain has been detected in sparrows in Thailand.
An outbreak of H5N1 was confirmed in Romania last week.
A British lab tested samples taken from swans which died in ponds near the Romanian village of Maliuc in the Danube Delta.
Local authorities have been culling thousands of birds, and the affected area has been placed under quarantine.
Maliuc is only 30km (20 miles) from Ceamurlia de Jos, where the country's first confirmed case of the virus was found.
The Danube delta is on the migratory routes of wild birds from Russia to North Africa.
Scientists fear the H5N1 virus could cause a human flu pandemic if it mutates into a form that can be spread from person to person.
The European Union has imposed a ban on imports of poultry from Romania and Turkey, and European Commission President Jose Manuel Barroso said "drastic measures" would be introduced if necessary.
Romania has completed the cull of domestic birds in Ceamurlia de Jos and Maliuc, where the quarantine will last for 21 more days. Authorities say people in the affected areas have all been vaccinated.
H5N1 BIRD FLU VIRUS
Principally an avian disease, first seen in humans in Hong Kong, 1997
Almost all human cases thought to be contracted from birds
Possible cases of human-to-human transmission in Hong Kong and Vietnam, but none confirmed
In the two villages, officials are spraying homes with disinfectant, concentrating on kitchens where infected poultry meat might have been kept.
Anyone entering or leaving the Delta area - vehicles, pedestrians and even trains - must pass through pools of disinfectant.
Romanian Agriculture Minister Gheorghe Flutur is confident that the virus has been isolated early enough to prevent its spread.
"On a 10-kilometre [six-mile] radius around Ceamurlia de Jos, the tests [for bird flu] are negative," he said.
Medical teams were visiting homes in the affected areas to establish how many people might have been infected, Health Minister Eugen Nicolaescu said.
Turkish authorities said the situation there was under control. The state-run Anatolia news agency says nine people have had blood tests after fears that they may have been infected with bird flu, although none was showing symptoms of illness.
Initial tests carried out after some 1,000 chickens died in the town of Patnos, near the border with Iran, found no traces of the deadly virus although final results will not be available before five or six days.
Last week, tests on dead birds in north-west Turkey confirmed the H5N1 strain, sparking fears that the virus might soon spread across Europe.
The H5N1 strain remained largely in South-East Asia until this summer, when Russia and Kazakhstan both reported outbreaks
Scientists fear it may be carried by migrating birds to Europe and Africa but say it is hard to prove a direct link with bird migration