BEIJING, May 20-- China's Ministry of Agriculture confirmed Saturday that an outbreak of H5N1 bird flu at Shijiping Village in Yiyang city of Hunan Province has killed more than 11,000 heads of poultry.The Ministry of Agriculture and the Hunan provincial government immediately implemented an emergency plan to deal with the outbreak, culling a further 52,800 birds to prevent any spread of the disease.Agriculture officials say that the outbreak had brought under control.The last reported cases occurred on March 1, when a batch of chickens suddenly died in a market in Lhasa, capital of southwestern Tibet, which were confirmed to have contracted the H5virus, according to the ministry. Some 680 chickens died and another 6,990 birds were culled.A new bird flu outbreak has been warned of late by Zhong Nanshan, a SARS expert and president of the Chinese Medical Association.Millions of birds have been slaughtered in order to combat the pandemic in China, which has also launched a massive effort to vaccinate poultry.Animal quarantine authority in Guangzhou, capital city of Southern China's Guangdong province, has pushed for the sales of the vaccinated chickens with rings marking the approved quality tied on the chicken legs.Poultry buyers began to pay more heed to the quarantine certificates issued by the authority to keep away from the pandemic.