BEIJING - China's quality watchdog said Thursday that it decided to suspend supplies of live poultry to Hong Kong after a dead chicken there tested positive for the highly pathogenic H5N1 virus.

The suspension, which started Wednesday, will last 21 days, according to the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ).

The AQSIQ has taken measures to actively deal with the situation after it was informed of the case that was found on Tuesday, AQSIQ Spokesman Li Yuanping said at a regular press conference.

The AQSIQ will maintain close contact and work together with the Hong Kong Special Administrative Region (HKSAR) government to jointly step up measures in controlling the epidemic, Li said.

The AQSIQ has ordered local quality authorities in Guangdong and Hainan provinces to strengthen quarantine inspection at ports to prevent the spread of avian flu, Li said.

Local entry-exit quality watchdogs are also required to promote prevention, control and monitoring of the disease, and boost disinfection and personnel protection work in registered farms that produce poultry for the city, Li added.

The HKSAR government raised the city's response level for bird flu to "serious" from "alert" following the discovery of the virus. More than 17,000 chickens started to be culled at a poultry market in the city on Wednesday.