PHNOM PENH, Cambodia (AP) _ A Cambodian village where 1,200 ducks dropped dead in a new outbreak of bird flu will be closely monitored for 30 days to prevent the disease from spreading, an official said Sunday.

Animal health officials will continue collecting samples from poultry in the village and a two-mile radius around it to test for bird flu, said Kao Phal, director of the Agriculture Ministry's animal health department.

He said another 400 ducks were killed by health authorities, part of the 1,600 on the small village farm where the outbreak began.

The ministry on Saturday confirmed the outbreak of H5N1 virus among ducks in Rokar Chuor Timuoy village in Prey Veng province, 30 miles southeast of the capital Phnom Penh.

Some of the affected ducks began falling sick on Aug. 2, and more than 1,000 of them dropped dead in following days.

This latest outbreak prompted Agriculture Minister Chan Sarun to urge people across the country to be on ``high alert'' for bird flu. In a nationwide broadcast, he ordered strict enforcement of the ban on poultry imports from neighboring countries or poultry trade near the stricken village.

Ly Sovann, director of the Health Ministry's disease surveillance bureau, said Sunday there are no signs yet that any villagers were infected by the virus.

The H5N1 virus, which re-emerged in Asia in late 2003, has killed at least 138 people worldwide, including six in Cambodia.