Western Europe flooding kills at least 44

At least 42 people have died in Germany and dozens are missing as swollen rivers caused by record rainfall across western Europe swept through towns and villages, leaving cars up-ended, houses destroyed and people stranded on rooftops.

Eighteen people died and dozens were unaccounted for around the wine-growing region of Ahrweiler, in Rhineland-Palatinate state, police said, after the Ahr river that flows into the Rhine broke its banks and brought down half a dozen houses.

Another 15 people died in the Euskirchen region south of the city of Bonn, authorities said.

People in region were asked to leave their homes.

In Belgium, two men died due to the torrential rain and a 15-year-old girl was missing after being swept away by an overflowing river.

Hundreds of soldiers and 2500 relief workers were helping police with rescue efforts in Germany.

Tanks were deployed to clear roads of landslides and fallen trees and helicopters winched those stranded on rooftops to safety.

About 200,000 households lost power due to the floods.

In Ahrweiler, two wrecked cars were propped steeply against either side of the town's stone gate and locals used snow shovels and brooms to sweep mud from their homes and shops after the floodwaters receded.

"I was totally surprised. I had thought that water would come in here one day, but nothing like this," resident Michael Ahrend told Reuters.

"This isn't a war - it's simply nature hitting out. Finally, we should start paying attention to it."

The floods have caused Germany's worst mass loss of life in years.

Flooding in 2002 killed 21 people in eastern Germany and more than 100 across the wider central European region.

Chancellor Angela Merkel expressed her dismay.

"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."

In the US for a farewell visit before she steps down following a federal election in September, Merkel promised financial aid for those affected.

"You can trust that all branches of government, federal, state and local, will join forces to do everything they can to save lives, avert danger and alleviate hardship," she said.

In Belgium, about 10 houses collapsed in Pepinster after the river Vesdre flooded the eastern town and residents were relocated from more than 1000 homes.

The rain also caused severe disruption to public transport, with high-speed Thalys train services to Germany cancelled.

Traffic on the river Meuse is also suspended as the major Belgian waterway threatened to breach its banks.

Downstream in the Netherlands, flooding rivers damaged many houses in the southern province of Limburg, where several care homes were evacuated.

In addition to the fatalities in the Euskirchen region, another nine people, including two firefighters, died elsewhere in North Rhine-Westphalia.

In the town of Schuld, houses were reduced to piles of debris and broken beams.

Roads were blocked by wreckage and fallen trees.

"It was catastrophic," said 65-year-old pensioner Edgar Gillessen, whose family home had been damaged.

"All these people living here, I know them all. I feel so sorry for them, they've lost everything. A friend had a workshop over there, nothing standing, the bakery, the butcher, it's all gone. It's scary. Unimaginable."

Weather experts said that rain in the region over the past 24 hours had been unprecedented as a near-stationary low-pressure weather system also caused sustained local downpours to the west in France, Belgium and the Netherlands.

More than 90 people have died after severe flooding in western Germany and Belgium, as rescuers continue to search for survivors.

At least 81 of the fatalities occurred in Germany, while there have been 12 deaths in Belgium, according to local media reports.

A total of 1,300 residents remain missing in the Ahrweiler district in the state of Rhineland-Palatinate, the district government said.

In the village of Schuld and elsewhere, houses were swept away after rivers burst their banks following days of extreme rainfall.

Speaking from Washington on Thursday, Angela Merkel expressed her sorrow at the events unfolding in her home country, calling it a day "characterised by fear, by despair, by suffering".

Her potential successor as chancellor, Armin Laschet, the premier of the badly-affected state of North Rhine-Westphalia, blamed the climate crisis for the catastrophe.

"We will be faced with such events over and over, and that means we need to speed up climate protection measures... because climate change isn't confined to one state," he said.

Deaths have been reported in Belgium too, with the mayor of Liège ordering residents to evacuate their homes on Thursday. The Netherlands and Luxembourg have also been affected by severe flooding.