PARIS, Jan. 11 (Xinhua) -- France has elevated its bird flu risk alert from "weak" to "moderate" on all of its territory, according to an order issued by the French Agriculture Ministry Friday.

    The decision was made after the highly pathogenic H5N1 strain was discovered Thursday in three dead swans in the southwest of England, according to the ministry.

    There are six levels of risk in France: unimportant 1, unimportant 2, weak, moderate, high and very high.

    The order took effect immediately, according to the ministry.

    Domestic birds and poultry are being protected in an attempt to prevent contact with wild birds. There will also be stringent veterinary checks.