At least 92 people have now been confirmed dead in the heavy floods which have devastated western Germany and caused the country’s worst mass loss of life in years.
More than 1,300 people also remain missing in the Ahrweiler district south of Cologne, as of Friday morning, the district government said on Facebook.
Authorities have ordered the evacuation of several villages below the Steinbach reservoir near the city amid fears the dam there could break.
One dam close to the Belgium border, the Rurtalsperre, was flooded overnight while another, the Steinbachtalsperre, is unstable.
Belgium itself has reported 11 deaths.
Mobile phone networks have collapsed in some of the flood-stricken regions across Germany, which means that family and friends were unable to track down their loved ones.
Entire communities lay in ruins after swollen rivers swept through towns and villages in the states of North Rhine-Westphalia and Rhineland-Palatinate.
Today houses have collapsed in Erftstadt near Cologne, and rescue crews were struggling to help residents who had returned to their houses despite the warnings, officials said on social media.
Many people were still in the houses and several were missing, added the Cologne district government.
A gas leak was further hampering rescue workers as they tried to reach stranded people by boat.
In the town of Schuld yesterday, houses were reduced to piles of debris and broken beams.
Roads were blocked by wreckage and fallen trees and fish flapped and gasped on puddles of water in the middle of the street.
“We have had two or three days of constant rain. Or maybe four, I lost track,” said Klaus Radermacher, who has been living in Schuld for 60 years.
“I saw the pizza store getting flooded, half an hour later the bakery was flooded.
“There is a camping ground up there, so caravans and campervans came floating past, gas tanks.
“We were powerless against it. It came so fast, I’ve never seen anything like it.”
Hundreds of soldiers are helping police with the rescue efforts, using tanks to clear roads of landslides and fallen trees, while helicopters winched those stranded on rooftops to safety.
The North Rhine-Westfalia parliament will hold an emergency meeting on Friday.
German Interior Minister Horst Seehofer told magazine Spiegel that the federal government aimed to provide financial support for the affected regions as quickly as possible, adding it should go to the cabinet for approval on Wednesday.
Flooding in 2002 killed 21 people in eastern Germany and over 100 across the wider central European region.
Chancellor Angela Merkel said her thoughts are with the family of those affected as she said: “I am shocked by the catastrophe that so many people in the flood areas have to endure.
“My sympathy goes out to the families of the dead and missing.”