Bulgaria said on Thursday it had detected bird flu in three backyard farms in a village in the south of the country near to the Turkish border and suspected it was the feared H5N1 strain of the virus.

"It´s proven that it´s bird flu, we don´t know the exact strain yet. We are working on the presumption that it is a highly pathogenic strain of H5N1," Agriculture Minister Nihat Kabil told reporters.

Bulgaria reported four cases of H5N1 infection in wild swans earlier this year, but has not suffered to the same extent as neighbors Turkey in the south and Romania in the north. This is the Balkan country´s first avian flu case in domestic birds.

Bird flu killed four children in eastern Turkey earlier this year, while Romania has reported dozens of outbreaks in birds.

In the current Bulgarian outbreak, 243 chickens and turkeys have either died or been culled and another 480 be destroyed by the end of the day in the village of Slanchogled, in southern Bulgaria, near the border with Turkey and Greece.

"Mass deaths among domestic birds have been registered in the village of Slanchogled. Rapid tests established a bird flu virus. We are putting the village under quarantine before final results show the strain," Kabil said.

A 3-km (two mile) quarantine zone has been set up around the village, including an area of seven more villages with a total of 2,100 domestic birds, to try to prevent the spread of the virus.

Kabil said he had ordered all eggs and poultry products in Slanchogled to be destroyed and have sent veterinary teams to disinfect the roads and supervise the poultry in a larger, 10-km protection area around the outbreak site.

The Balkan country will know whether the strain of the virus was from the H5 strain in four days and will send samples to the EU-certified laboratory in United Kingdom for further testing.

Kabil called to Bulgarians to observe higher hygiene and appealed to the farmers to keep their poultry indoors. He said the reason for the infection was being investigated, but said there was no bird migration at the moment.

He said there was no immediate danger for the health of the people, as neither of the birds from the village were offered for sale and the two people that have been in contact with the infected birds are under medical surveillance.

"The infection will be contained and we will not allow it to jump to humans," Kabil said.