HONG KONG -- Authorities here slaughtered 2,700 birds and banned live poultry imports from mainland China for as long as 21 days after a routine inspection Saturday found chickens in one of the city's poultry markets infected with the dangerous H5N1 bird-flu virus.

While there is little immediate threat to humans from the infected birds, the discovery revives concerns that the disease could still be a problem with poultry flocks in southern China -- although it isn't yet clear whether the infected birds came from local or mainland Chinese farms.