"We mourn with those that have lost friends, acquaintances, family members," German President Frank-Walter Steinmeier said during a visit to Erftstadt in the state of North Rhine-Westphalia, where the disaster killed at least 43 people
Some 133 people have died in the flooding in western Germany, the country's worst natural disaster in more than half a century. That included about 90 in the Ahrweiler district south of Cologne, according to police. Hundreds of people are still missing.
Around 700 residents were evacuated late on Friday after a dam broke in the town of Wassenberg near Cologne, authorities said.
Steinmeier called the flooding a tragedy and said it would take weeks before the full damage, expected to require several billions of euros in reconstruction funds, could be assessed.
Armin Laschet, state premier of North Rhine-Westphalia and the ruling CDU party's candidate, said he would speak to Finance Minister Olaf Scholz in the coming days about financial support.
In Belgium, the death toll rose to 24, according to the national crisis centre, which is coordinating the rescue effort.
"Unfortunately, we have to assume that this figure will continue to rise in the coming hours and days," the centre said in a statement. About 20 people are still missing.