By Janis Laizans and Radovan Stoklasa NYSA, Poland/OSTRAVA, Czech Republic (Reuters) -Poland's historic city of Wroclaw readied buses for possible evacuations on Tuesday and the zoo called for volunteers to protect animals from rising water as the death toll in three days of devastating floods across central Europe rose to 21.

Soldiers and volunteers in southwestern Poland have laid sandbags near swollen rivers around the city of Wrocław to protect homes and businesses after days of flooding across Central Europe. Poland joins Austria, the Czech Republic and Romania in being hard hit by floods following record rains in the region starting last Thursday.