More testing is needed before China can confirm whether a soldier who died in Beijing in 2003 was an early case of bird flu, the Health Ministry said Monday.

The case, first disclosed last month in a letter by Chinese researchers to a US medical journal, has raised questions about whether China failed to detect and report an early human infection of bird flu.

The 24-year-old man who died in a military hospital on December 3, 2003, was first diagnosed with SARS. The Health Ministry said scientists in Beijing tested samples from the dead man in 2004 and last year and found "possible" infection with the H5N1 bird flu virus.

However, under World Health Organization and Chinese regulations, "confirmation still requires parallel testing" by another laboratory, the Health Ministry said. "Currently, work on a definite diagnosis on this case is under way."

The 2003 fatality came two years before China reported its first bird flu death but just a few months before the virus tore through Vietnam and Thailand.

Confirmation of early human bird flu infections in China would firm up theories that the virus originated in southern China.

The latest outbreak of the H5N1 bird flu virus has killed more than 130 people worldwide, 12 in China, and ravaged Asian poultry stocks since late 2003.

The bird flu outbreaks in late 2003 followed on the heels of severe acute respiratory syndrome, or SARS, which emerged in southern China in late 2002.

The findings by the Chinese scientists, whose letter was published in the June 22 edition of the New England Journal of Medicine, raised the possibility that other SARS cases might have been H5N1 infections.

A WHO spokesman said Friday the UN agency had asked the Health Ministry whether other suspect cases are being tested and was waiting for a response.