Asia's death toll from bird flu rose to 50 on Wednesday when health officials and a hospital doctor confirmed two additional deaths in Vietnam.

A 10-year-old girl who tested positive for the H5N1 bird flu virus died of lung failure hours after she was admitted to St. Paul's Hospital in Hanoi on March 27, a hospital doctor said on condition of anonymity.

Test results by the National Institute of Hygiene and Epidemiology were released on Monday, the doctor said.

In addition, Vietnam's Health Ministry confirmed one other previously unreported death, although officials there gave no details about when the patient died, where they were from, or their age or gender.

Vietnam has reported a total of 16 deaths from bird flu since the country's latest outbreak began in late December.

Since a severe strain of the disease started surging through poultry farms in Asia in December 2003, a total of 50 people have died in the region _ 36 from Vietnam, 12 from Thailand and two from Cambodia.

A different strain of bird flu, the H7 strain, struck poultry farms in North Korea last month, killing thousands of birds, according to a U.N. expert who visited the area.

North Korea has culled some 219,000 birds on three farms within a five-kilometre radius of Pyongyang, the North's capital, in a bid to stop the disease's spread, said Hans Wagner, a veterinarian for the U.N. Food and Agriculture Organization.

H7 is one of two avian flu strains other than H5N1 which can cause illness in humans, but the outbreaks are not as severe as those caused by the H5N1 strain.