ANKARA (Reuters) – Turkey announced on Sunday that three people had tested positive for bird flu in the Turkish capital, Ankara, marking a further westward advance of the infection toward the frontiers of Europe.

Ankara Governor Kemal Onal told the state-run Anatolia news agency that two children and one adult had been diagnosed with the infection; but it was not clear if they were suffering from the deadly H5N1 strain that has killed three people in the remote east of the country.

The agency said a five-year old boy had been admitted to hospital with suspected bird flu in Corum in central Turkey.

The virus had been spreading since October among flocks in Turkey, having advanced from Southeast Asia; but no people in Turkey had been reported infected until last week.

The emergence of human cases of the flu in the Van area, near the borders of Iran and Armenia, raised fears the disease might advance to major Turkish population centres and to Europe.

It seems highly likely that the children who died in Van region caught the virus directly from chickens. But world health authorities are concerned that human exposure to the bird flu could lead to emergence of a mutation allowing easier transmission between humans and raising the prospect of a pandemic.