(QHA) -

Hong Kong has begun a mass cull of around 20,000 chickens after the deadly H7N9 bird flu virus was discovered in a batch of poultry imported from mainland China, the Guardian reports.

Officials wearing masks and protective suits piled dead chickens into black plastic bags at a wholesale market in Hong Kong where the virus was discovered on Monday.

"It (the culling) has started. It begun at around 10am," an Agriculture, Fisheries and Conservation Department spokesman said.

The chickens would be given a "chemical treatment" to kill them, after which they would be sent to landfill, the spokesman said.

The culling operation is set to last for ten hours.

The positive H7N9 reading was discovered in chickens at Cheung Sha Wan market on Monday, which will be closed for 21 days until February 18 for cleaning and disinfection.

Fears over the virus have grown following the deaths of two men in Hong Kong since last December.