The latest death toll from the floods in western Germany this month is 180, of which about 150 are still missing, officials said Friday.
With more rain expected this weekend, German weather services needed more attention.
The Rhineland-Palatinate region, most affected by the storm, according to police, 132 have now been confirmed dead and 766 injured.
Police search by helicopter with around 30 sniffer dogs.
“I have no way of knowing if we can find all the dead,” Lewentz said.
In the vicinity of North Rhine-Westphalia, 47 people have died.
Cologne police said they were looking for two people who had disappeared or could not be found.
One person also died in Bavaria, while Belgium lost 36 people, bringing the total population of Europe to 216.