Belgium has held a day of mourning for the victims of last week’s devastating floods, while German chancellor Angela Merkel made her second visit to the region worst hit by the disaster that left nearly 200 people dead in the two nations.

The Belgian king and queen visited the eastern town of Verviers on Tuesday to console people who had lost loved ones or most of their possessions as torrents swept through villages in eastern Belgium, taking at least 31 lives.

“We will not abandon you,” prime minister Alexander De Croo wrote in a letter published in local newspapers. “We will do everything possible to support you.”

Some 70 people are still missing or have been unable to be contacted after massive rains turned streets in eastern Belgium into deadly torrents of water, mud and debris.

Flags flew at half mast and at noon, sirens wailed throughout the nation, followed by a moment of silence.

Help is pouring in from across the country and some 10,000 volunteer workers have offered to visit the hilly region to start the clean-up once the waters have receded enough.

In Germany, Mrs Merkel made her second visit to the western region hit by flash floods as work continued to clear up piles of mud-caked debris and find any more victims of last week’s disaster.

In the town of Bad Muenstereifel, she started her tour by visiting a warehouse where donations were being stored.

So far, 196 people have been confirmed dead following the flooding — 165 in Germany on top of the 31 in neighbouring Belgium.

Mrs Merkel and Mr De Croo have promised quick financial aid and a redoubled political focus on curbing climate change.

European Union environment ministers underscored the point when they met in Slovenia on Tuesday to assess last week’s massive and costly EU plan to contain climate change.

Germany’s deputy environment minister, Jochen Flasbarth, said that “we do not have an alternative” to delivering on that plan.

EU Commission vice president Frans Timmermans agreed.

“What we’ve seen last week was a small reminder of the fact that the cost in human lives, but also material costs of non-action are way, way higher than the cost of acting,” Mr Timmermans said.

“Humanity will be confronted with very erratic weather patterns: 50 degrees (Celsius) north-west Canada, 40 degrees in Siberia, 40 degrees in central Europe. The floods, droughts, agriculture’s dealing with wildfires. That is a consequence of the climate crisis,” he said.

Mr Timmermans is the chief architect of the massive proposals to spend billions and force industry into drastic reforms to help cut the bloc’s emissions of the gases that cause global warming by 55% this decade.