BEIJING - A 19-year-old Chinese soldier has died of the H5N1 strain of bird flu, the country's 16th reported death from the virus, the World Health Organization said Tuesday.

The man, stationed in the southern province Fujian, died Sunday after being taken to hospital May 14 with a fever and cough, said Joanna Brent, a spokeswoman for WHO's Beijing office.

The Chinese Health Ministry, which gave the soldier's surname as Cheng, informed WHO about the death Sunday but did not give any details about his case, including how he contracted the disease or exactly where he was posted, Brent said.

"We're always concerned about cases of bird flu," she said.

The People's Liberation Army has put all the man's close contacts under observation and "so far there are no clinical abnormalities. We understand it's an individual case," Brent said.

One of China's two other reported human cases of bird flu this year was a farmer in Fujian but Brent said Cheng was not near that area.

A woman who answered the telephone at the Health Ministry's press office said she could not provide any details of the case.

Telephones were not answered at the Ministry of National Defence.

Last year, it was disclosed new tests on the body of a 24-year-old soldier who died in 2003 in Beijing confirmed he succumbed to bird flu - one of the earliest deaths in a resurgent wave of bird flu that swept through the region.

The military has yet to provide a promised virus sample from that case, WHO has said.

While H5N1 is most commonly passed from sick poultry to humans, WHO has said Cheng's case was China's 24th of 25 human infections that occurred without a reported outbreak among poultry - indicating a weak surveillance system and a still-circulating virus.

Experts worry that if outbreaks are not controlled, H5N1 could mutate into a form more easily transmitted between people, potentially causing a worldwide pandemic.

Last week, China's Xinhua News Agency said the farmer from Fujian, Li Yinxiu, had been discharged from the hospital after three months of treatment. She developed symptoms after coming in contact with dead poultry.

Bird flu has killed at least 188 people since H5N1 started ravaging Asian poultry flocks in late 2003, WHO said.