Officials said the remains of 22 grey geese were being examined for the deadly flu virus in Koblenz, western Germany. They said it would not be clear whether the birds had died from a virus until Tuesday evening at the earliest, and that it would be several days before scientists knew whether the virus were dangerous.

"Nothing has been proven yet," said a spokeswoman from the state environment ministry, adding that dead birds were not a rarity and that there is no cause for panic.

The dead geese were found on a pond that serves as a resting place for migratory birds. Police officers at the scene reported seeing several of the birds die while suffering severe cramping. The geese were sharing the pond with other types of birds, which showed no signs of the illness. A water sample from the pond is also being examined.

Officials: No cause for panic

The nearby city of Neuwied has advised people to remain calm. The city's mayor, Reiner Kilgen, said that all the necessary precautions to prevent an outbreak of bird flu had been taken, and that there was no threat to the population. Kilgen said that officials were treating the incident seriously, however.

"You have to assume the worst, so that you don't do anything wrong," he said.

Three further dead geese were found at pond near Göttingen in the central German state of Lower Saxony. Officials there said the birds were most likely too weak for their migratory journey. "Every year, there are bird deaths in this area," Jürgen Gremmel of the state's veterinary office told the Associated Press.

Concern over H5N1 strain

Concern is mounting that a strain of the avian flu virus harmful to humans -- the H5N1 strain -- could spread in Europe. Russia has confirmed cases of birds killed by the H5N1 strain, and tests are being conducted on dead birds in Croatia, Hungary and Portugal.

Germany has ordered that free range poultry be kept indoors in the hope of limiting the spread of the disease, which is carried by migratory birds.