Vietnamese veterinary officials say bird flu has infected chickens on two farms in the capital, Hanoi.

Officials say authorities have slaughtered the surviving chickens after a number of birds died on the farms in Hanoi's Dong Anh district.  Authorities say some of the dead chickens tested positive for the often-fatal H5N1 strain of the bird flu virus.

Wednesday's announcement follows one from Ha Tay province, where a bird flu outbreak was reported Tuesday.

Last month, the virus was identified on farms in the provinces of Hai Duong and Vinh Long.

Bird flu emerged in Vietnam in 2003 and has killed 42 people in the country since then.

It has not reported any human cases of bird flu since late 2005. The disease has killed 167 people worldwide.

Some information for this report was provided by AFP, AP and Reuters.