TROOZ, Belgium, July 16 (Reuters) - Belgium declared a national day of mourning next week as the death toll from burst rivers and flash floods in the south and east of the country rose to 20 on Friday, with another 20 people missing. "What should have been beautiful summer days suddenly turned into dark and extremely sad days for our fellow citizens," Prime Minister Alexander De Croo told a news conference. "These are exceptional circumstances that our country has not seen before." A week of rain finally came to an end after reaching levels in some places normally expected once in 200 years. But several communities across parts of Belgium were nervously watching as the river Meuse, which flows through the city of Liege in eastern Belgium, continued to rise and threatened to overflow. Others were trying come to terms with disaster. "We did work, we renovated everything, we"re losing everything we"ve got. Now we have to start from zero and work at it little by little to put it back in order." said Sylvia Calvo Lorente, 33, surveying damage in her home in the small town of Trooz near Liege. In the eastern town of Verviers, the swollen river was still rushing through neighbouring streets, where people gingerly tried to salvage ruined shops, homes and cars. "We made it through COVID, we were hoping we"d get back on our feet and now look!" a shopkeeper said through tears in a pause from his work. A damaged vehicle is seen in the river, following heavy rainfalls in Verviers, Belgium, July 16, 2021. REUTERS/Yves Herman A damaged vehicle is seen next to the river, following heavy rainfalls, in Pepinster, Belgium, July 16, 2021. REUTERS/Yves Herman Vehicles damaged by heavy rainfalls are pictured in Pepinster, Belgium, July 16, 2021. REUTERS/Yves Herman 1/5 A damaged vehicle is seen next to the river, following heavy rainfalls, in Pepinster, Belgium, July 16, 2021. REUTERS/Yves Herman Several towns and villages were submerged, including Pepinster near Liege, where around 10 houses collapsed. Belgium"s king and queen visited the town on Friday, wading through flooded streets. The government set next Tuesday as a day of mourning and decided to tone down festivities for Belgian National Day the day after. Interior minister Annelies Verlinden said 20 people had lost their lives, with a further 20 missing. The crisis centre, which is coordinating rescue efforts, urged people in the affected areas to avoid all travel. Belgium has called on the European Union"s civil protection mechanism, resulting in contributions from France, Austria and Italy, principally boats, helicopters and rescue personnel. It also received help from Luxembourg and the Netherlands, despite these countries also suffering from flooding. More than 250 foreigners, including helicopter pilots and divers, have come to aid the search. Over 20,000 people in the southern region Wallonia were without electricity. Others lacked clean water. Large parts of the rail network in southern Belgium were unusable, with certain sections of track swept away.