HANOI, Feb 4: Two more fatalities in Vietnam and one in Thailand lifted the regional death toll from bird flu to 16 on Wednesday as the World Health Organisation said no part of Asia was safe from the disease.

A US medical expert said that China, which confirmed another outbreak, probably already has human cases of bird flu.

Henry Niman, a bioengineer at Harvard Medical School, said precious time needed to prevent disaster was being lost because of China's failure to acknowledge the extent of the epidemic.

China insists no people have come down with the disease. It did not report any outbreaks until last Tuesday, since when confirmed or suspected outbreaks have been announced in a third of its regions.

But in human terms Vietnam, where 11 people have now died from 15 confirmed cases, is the worst affected.

The latest victims were a 24-year-old man from the Vietnamese province of Lam Dong, and a 15-year-old girl from Tay Ninh in the south, health officials said.

Thailand, the only other nation to have acknowledged human fatalities from the disease, confirmed a fifth death, that of a six-year-old boy.

Meanwhile, WHO warned Wednesday that no part of Asia should consider itself immune from the avian flu, which it said appeared to be older and more established than initially thought.

"The speed with which the virus is spreading suggests that nowhere in the region is safe," said Peter Cordingley, spokesman for the WHO's Manila-based Western Pacific office. "The virus is spreading faster than we can get to it."

As well as China, Vietnam and Thailand, bird flu outbreaks have also been confirmed in Cambodia, Indonesia, Japan, Laos and South Korea, Taiwan and Pakistan.

WHO has warned that the H5N1 virus could kill millions across the globe if it combined with a human influenza virus to create a new highly-contagious strain transmissible among humans.

It says the further culling of birds, a ban on poultry imports from affected areas and improved hygiene measures were essential to containing the virus.

More than 25 million chickens have died or been culled across Asia, with the disease believed to have been passed on to humans through direct contact with sick birds or their droppings.-AFP