Border areas between the Czech Republic and Poland were hit hard over the weekend.
Some bridges collapsed and homes were destroyed, while villages and towns in eastern Romania were submerged.
Poland's government was due to meet on Monday morning local time to call a state of disaster.
A man drowned and a second person is believed to have died in the deluge in Poland. (EPA PHOTO)
While rivers in the Czech-Polish border area were starting to recede, flooding was widening to more parts and leaving bigger cities in both countries on alert.
In the Czech Republic, a rising Morava River overnight put Litovel, a city 230km east of the capital Prague with a population of nearly 10,000, around 70 per cent under water and shut down schools and health facilities, its mayor said in a video on Facebook.
Flooded parts of northeastern Czech regional capital Ostrava forced closures of a power plant supplying heat and hot water to the city as well as two chemical plants.
More than 12,000 people have been evacuated in the Czech Republic, Prime Minister Petr Fiala said on social media platform X as he called an extraordinary government session for Monday.
Czech Television reported the first confirmed victim, adding to casualties across the region.
Days of heavy rain in the Czech Republic and other central European nations led to the flooding. (AP PHOTO)
In Romania, the flooding killed six people over the weekend, and an Austrian firefighter died on Sunday.
A man drowned in Poland on Sunday. Infrastructure Minister Dariusz Klimczak said he had information on a second death, which Reuters could not immediately verify.
Polish Deputy Minister of Internal Affairs Czeslaw Mroczek told Polish Radio thousands of firefighters, police officers and soldiers had battled floods in the past 24 hours while the government was still working to determine the scale of damage.
"The government, as announced, will make a decision to introduce a state of natural disaster ... We are consulting with local governors," he said.
Heartfelt solidarity with all affected by the devastating floods in Austria, Czech Republic, Hungary, Poland, Romania and Slovakia. — Ursula von der Leyen (@vonderleyen) My thoughts are with the victims and their families.Thank you to all those helping for their tireless work. The EU stands ready to support.September 15, 2024
Slovakia's capital Bratislava and Hungarian capital Budapest were both preparing as the River Danube rose.
In Austria, the levels of rivers and reservoirs fell overnight as rain eased but officials said they were bracing for a second wave as heavier rain was expected in the coming hours.
European Commission President Ursula von der Leyen, in a message on X, sent words of solidarity to those affected by flooding and said the EU would provide support.
11°C