Turkish officials put nine people under medical observation after reports that 40 pigeons in their neighborhood mysteriously died, authorities said Friday, as officials confirmed that earlier bird deaths were caused by a virulent strain of bird flu, AP reported. In Kiziksa, where the earlier deaths occurred, veterinary officials in protective suits were culling the few remaining birds in the village. Officials already have culled some 8,600 birds in the western Turkish village as a precaution, and vowed to kill all within a 3-kilometer (2-mile) radius as a precaution against the spread of the H5N1 strain, which is highly contagious among birds but difficult for humans to contract. A veterinary official said the work would finish later Friday. In the neighboring province of Manisa, authorities put nine people under medical surveillance on Thursday after a man reported that some 40 pigeons had died within the past two weeks, the Anatolia news agency reported Friday. Samples were sent for laboratory testing in Izmir, western Turkey, the agency said.