"The greatest enemy of the flood defences is an animal called the beaver. They live everywhere along the levees on the Vistula (river) and cause a lot of damage to them," Jerzy Miller told reporters.

An estimated 50,000 of the large, mostly nocturnal, semi-aquatic rodents live in Poland where they enjoy a degree of protection, animal welfare services say.

But local authorities have upped hunting quotas for the animals in the wake of the floods.

"Beavers dig tunnels in the flood defences, weakening them from inside. But they are not alone, there are also water voles," Pawel Fratczak, Poland's national fire brigade spokesman said.

Torrential rain in Poland's mountainous south have caused rivers, including the Vistula, Poland's largest, swell to levels unseen in more than a century.

Flood defences have already given way near the southeastern town of Sandomierz and in Plock, central Poland, causing flooding in several locations in those regions.

Thousands have been evacuated across the country, but according to Fratczak thousands more have refused to leave their homes regardless of the risk posed by rising flood waters.

Forecasters predicted intermittent rain and storms across Poland until the middle of the week as the flood crest moves north on the Vistula and the Oder among others.

Poland's government Tuesday pledged two billion zloty (481 million euros, 586 million dollars) in aid for people who lost their homes to rising waters.

Last week, Tusk said the cost of the flood damage could reach 10 billion zloty (2.43 billion euros, 3 billion dollars).

In 1997, Poland suffered its worst flooding in centuries which killed 54 people, caused billions of dollars in damage and forced the evacuation of over 150,000 people.

del.icio.us	Digg	Reddit
YahooMyWeb	Google	Facebook