HANOI, May 24 (Xinhua) -- Over 400 fowls in Vietnam's central Ha Tinh province have died with unidentified causes, local newspaper Vietnam Agriculture reported Thursday.

    Specimens from the fowls in several farms in Nghi Xuan district are being tested for bird flu viruses, the report said.

    Bird flu has hit five Vietnamese provinces, namely Quang Ninh, Son La and Nam Dinh in the northern region, Nghe An in the central region, and Dong Thap in the southern region, and southern Can Tho City since early this month.

    Bird flu outbreaks in Vietnam, starting in December 2003, have killed and led to the forced culling of dozens of millions of fowls in the country.