A 21-day suspension of live poultry shipments from Guangdong Province to Hong Kong has been imposed for fear of deadly avian flu spreading, an official at the Guangdong Provincial Administration of Quality Supervision, Inspection and Quarantine said on Wednesday.

Live chickens, pigeons and chicks are affected. The suspension, which became effective on Tuesday, does not involve frozen poultry.

Hong Kong's Food and Health Authority has informed mainland authorities that some 100 breeding and sentry chickens died on Sunday at one live poultry farm in Hong Kong, where 60,000 chickens were being raised.

Sentry chickens are deliberately left unvaccinated against bird flu to act as warning signs of an outbreak. Hong Kong has been using this method since 2003.

Lab work on samples from the dead birds returned positive tests for the deadly strain of H5 virus. All the other poultry on the farm were culled.

It was the second bird flu outbreak in Hong Kong this year. The first was on June 6, when excrement samples collected in two live poultry markets in Hong Kong tested positive for the deadly strain of H5N1 virus, leading to a cull of all live poultry and trading suspension of poultry products in the city.

Editor: Yan