AMSTERDAM (REUTERS) - Thousands of people fled their homes in the southern Netherlands on Friday (July 16) as rising waters broke through a dyke and swamped cities.

Prime Minister Mark Rutte declared a national disaster in the southern province of Limburg, which is sandwiched between badly flooded areas in western Germany and Belgium.

Authorities were preparing to evacuate large parts of the city of Venlo on Friday afternoon, and told people in the smaller municipality of Meerssen to leave their properties.

"There is a large hole in the dyke... Immediately leave your home and get to safety," emergency services in Meerssen said in an online alert. Families were told to turn off their electricity and gas supplies.

Much of the Netherlands is below sea level, protected by a complex system of ancient dykes and modern cement barriers that hold back water from the sea and rivers.

The military later managed to reinforce the dyke near Meerssen, the regional security body told L1 radio, but the evacuation order remained in place.

Hundreds of firefighters and soldiers were deployed to help reinforce other dykes and evacuate residents.

In Valkenburg, close to the Belgian and German border, floods engulfed the town centre, forcing the evacuation of several nursing homes and destroying at least one bridge.

Water levels on the Meuse and the Rur had already reached record levels on Thursday, surpassing those that led to large floods in 1993 and 1995, local authorities said.