NOVOSIBIRSK, May 22 (RIA Novosti) - Birds in three districts of West Siberia's Omsk Region have died of bird flu, a spokesman for the local emergencies ministry said Monday.

"An investigation showed that dead birds in three districts of the region were infected with avian influenza," the spokesman said, adding that quarantine had been imposed in the three villages where birds had died between May 15 and 19.

He added that 136 birds had died in six districts of the region since May 13.

The Emergency Situations Ministry said last month that around 1.1 million birds had died of the disease in Russia, and 0.3 million had been culled in measures to control the spread of the virus since the beginning of February.

No human cases of bird flu have yet been diagnosed in Russia.