However, Ukrainian officials noted that official confirmation is expected tomorrow.
"We have information that the strain H5N1 was detected," Vyacheslav Herman, deputy director of the state institute for biotechnology, said.
Ukraine had sent suspicious tissue from birds that demonstrated bird flu symptoms last weekend for laboratory tests to an institute in Russia and Britain. Petro Verbytsky, sacked as Ukraine's chief veterinarian earlier this week, emphasized that the data was preliminary, but he added that confirmation was expected on Friday.
Verbytsky is calling for the inoculation of all of Ukraine's 190 million head of domesticated poultry on small farms, according to the government news agency Ukrinform.
President Viktor Yushchenko earlier this week declared a state of emergency in affected areas, a measure that the Emergency Ministry said was key to stopping the spread of the disease to other parts of the country.
The Emergency Ministry, which is overseeing measures to contain the outbreak, is carrying out a cull of domesticated poultry in the affected areas on the Crimean peninsular in the Black Sea. So far, its staff has seized more than 29,000 birds in house-to-house checks in villages sealed off by an exclusion zone. The government is paying for killed birds from $3 for a chicken to $18 for a turkey.
An undisclosed number of new infections were discovered in Crimea today, said independent news agency UNIAN. It reported that medical teams have vaccinated nearly 10,000 people in the infected region.
The highly pathogenic H5N1 avian flu virus has killed almost 70 people in Asia, where it is endemic in poultry. Ukraine has not reported any cases of bird flu so far in humans.