Chinese authorities have found traces of a new bird flu virus that has killed six people in more areas in Shanghai, after authorities slaughtered over 20,000 birds at a large poultry market in the city.
The state-run Xinhua news agency said samples of the H7N9 virus were found at two markets selling agricultural products in the Minhang district of Shanghai.
The markets were near the Huhuai live poultry market where infected pigeons were discovered earlier in the week and where the culling was carried out.
The new strain of bird flu has infected 16 people in China, all in the east of the country.
The strain does not appear to be transmitted from human to human, but authorities in mainland China and Hong Kong said they were taking extra precautions.
Shanghai has banned all live poultry from other parts of the country from entering the city, and has now closed three markets to stem the spread of the virus.
Hong Kong's government said it is intensifying surveillance of travellers and poultry coming into the city.
The latest fatality of the virus was a farmer in the eastern province of Zhejiang. He was the second person from the province to die.
The first two deaths from the virus occurred in February but were not reported until late March.
Officials said the delay in announcing the results was because it took time to determine the cause of the illness.
An outbreak of Severe Acute Respiratory Syndrome (SARS) in 2003 killed about 800 people around the world.