China has found the H5N1 avian influenza virus in birds in the northwestern region of Ningxia, the Agriculture Ministry said, suggesting a fresh outbreak.

The National Bird Flu Reference Laboratory identified the virus on Thursday in samples taken from the town of Xuanhe in Ningxia's Zhongwei city, the ministry said late on Friday on its Web site (www.agri.gov.cn).

Measures had been taken to prevent the outbreak from spreading, it said. The announcement did not say whether the virus had been found in domestic or wild birds, or how many birds had died.

The northern province of Shanxi reported an outbreak of bird flu in poultry last month, which led to the culling of about 1.5 million birds.

The H5N1 virus has spread among birds across Asia, Europe and Africa. People who have close contact with infected birds can fall ill, even die. Scientists fear the virus will mutate into a strain that spreads between humans, sparking a wider outbreak.

China has reported about 40 outbreaks of bird flu in birds across a dozen provinces over the past year, and since November 12 people are known to have died from the H5N1 strain while six have survived.

The latest human case of bird flu was confirmed on June 15 in the southern boom town of Shenzhen, bordering Hong Kong, bringing the country's total human infections to 19. State media said earlier that the man had been in a critical condition.