At least 12 people died and thousands were affected when heavy rains caused three Polish rivers to flood, according to a Polish Defense Ministry spokesman.

The rains over the past week caused the Vistula, Odra and Warta rivers to flood, affecting some 20,000 people, according to the spokesman, Wieslaw Grzegorzewski.

Nine helicopters, more than 3,800 soldiers and 35 special boats were being used to help flooding victims, he said, and the ministry was doing its best to prevent further flooding damage.